Dispatching apparatus with a gas supply distribution system for handling and storing pressurized sealable transportable containers

ABSTRACT

The dispatching apparatus with a gas supply distribution system (300) basically comprises an automatic handler 301 and a vertical stocker (302). The vertical stocker has a frame (308) formed by an assembly of tubes supporting a plurality of support stations or bins (309) each provided with gas infectors (311) connected on the one hand to the gas injection valves of the container and on the other hand to a compressed ultra pure neutral gas supply installation. As a result, during the processing idle times, an adequate overpressure of said neutral gas is maintained in the interior space of the container enclosing the workpiece, e.g. a silicon wafer. The automatic handler (301) basically comprises a handling robot (305) having an extending arm (306) provided with gripping means (307) adapted to the container design. The handling robot (305) is affixed on an elevator (304) for vertical movement and is able to rotate about it. The automatic handler (301) is adapted to transfer of containers (100) between the vertical stocker and conventional conveyors ( 401, 402) or between the conveyors themselves.

FIELD OF INVENTION

The present invention relates to container handling and storing systemsand more particularly to a family of dispatching apparatus provided witha gas supply distribution system for handling and storing pressurizedsealable transportable containers. Each container encloses a work piece,typically a semiconductor wafer, in a protective gaseous environment.Said gas supply distribution system aims to maintain said protectivegaseous environment during the processing idle times.

COPENDING APPLICATIONS

Pressurized sealable transportable containers for storing asemiconductor wafer in a protective gaseous environment, U.S.application No. 08/101,599, filed Aug. 3, 1993.

Pressurized interface apparatus for transferring a silicon wafer betweena pressurized sealable transportable container and a processingequipment; U.S. application No. 08/102,076, filed Aug. 3, 1993.

Fully automated and computerized conveyor based manufacturing linearchitectures adapted to pressurized sealable transportable containers;U.S. application No. 08/101,608, filed Aug. 3, 1993.

The first application is directed to a family of pressurized sealabletransportable containers which store a single semiconductor wafer in aprotective gaseous environment having a positive differential pressurewith the outside ambient (e.g. the atmosphere). It is the essentialconstituent of this group of four inventions. The second application isdirected to a family of pressurized interface apparatus for interfacingthe container and a processing equipment. The role of the interfaceapparatus is to transfer said wafer from the container into a processingequipment for treatment and vice-versa without breaking said protectivegaseous environment. The third application is directed to a family ofdispatching apparatus with a gas distribution system for handling andstoring the containers during the wafer idle times between differentprocessing steps while still maintaining said protective gaseousenvironment. The fourth application is directed to the optimalintegration of above elements with conventional conveyor means and acomputer system to result in a fully automated and computerizedmanufacturing line which is modular, flexible and fully compatible withthe Continuous Flow Manufacturing (CFM) concept in a Computer IntegratedManufacturing (CIM) environment.

There are three major principles at the base of these inventions.

1. In essence, the container is adapted to store a single semiconductorwafer.

2. Except of course during treatment in the processing equipment, thesemiconductor wafer is permanently surrounded by a protective gaseousenvironment having a static pressure higher than the one of the outsideambient. To that end, the container is filled with a compressed ultrapure neutral gas. As a result, the container interior space has apositive differential pressure with respect to the outside ambient.Within the container, the protective environment is safe, clean andstill. This pressurized neutral gas constitutes said desired protectivegaseous environment which fully isolates the wafer from anycontamination existing in the outside ambient. Preferably, the gas iscontinuously rejuvenated through a high efficiency filter by a permanentconnection of the container to a supply installation of said compressedultra pure neutral gas, except during the very short times oftransportation in the manufacturing facility. Likewise, to that end, thepressurized interface apparatus and the dispatching apparatus areprovided with gas feeding means. Moreover, the container and thepressurized interface apparatus have been specifically designed so thatduring the transfer operations therebetween, the wafer is stillprotected by an efficient curtain or shower of said gas. Therefore,there is no isolation breakdown during the whole waferprocessing/treatment. Finally, fabrication of contamination-free wafersunder the conditions appropriate in ultra clean rooms is henceforthfeasible without the huge facilities that are usually required in thatrespect.

3. Usage of conventional conveyors. All these elements have beendesigned to be fitted with conventional conveyors, that are widelyrecognized as a convenient transportation system, fully adapted tomechanical automation and computerization.

DESCRIPTION OF THE PRIOR ART

Semiconductor wafers (hereinafter referred to as "wafers") are the basematerial for the production of VLSI chips. Wafers, usually stored incarriers or jigs, may only be handled and transported in extremely cleanenvironments, because even minute dirt or dust particles render themunusable for further processing. Therefore, control of particulatecontamination is imperative for cost effective, high-yield andprofitable manufacturing of VLSI chips. Because design rulesincreasingly call for smaller lines definition, it is necessary to exertgreater control on the number of particles and to remove particles witheven diminishing sizes. For instance, contamination particles may causeincomplete etching in spaces between conductive lines which in turn,result in electrical failures in the final chips.

Particles sizes down to 0.1 μm can still be very damaging in thesemiconductor processing because of the very small geometries employedtoday in fabricating the semiconductor devices integrated in the VLSIchips. Typical semiconductor processes today employ geometries which are0.5 μm in the manufacturing lines, therefore particles which havegeometries measuring greater than 0.05 μm substantially interfere withsuch 0.5 μm geometry semiconductor devices. Because, the trend of courseis to have even smaller and smaller geometries, which today in researchand development laboratories approach 0.1 μm and below, hencecontamination by even smaller particles becomes of paramount importance.

The main sources of particulate contamination are personnel, equipment,installation (including clean rooms) and chemicals. Particles within theequipments and chemicals are termed "process defects". To minimizeprocess defects, processing equipment manufacturers must prevent machinegenerated particles from reaching the wafers and suppliers of gases andliquid chemicals must deliver cleaner products. Particles given off bypersonnel and clean room facilities are certainly the most importantsource of contamination. Because they are easily ionized, they tend tocause defects onto the wafer surface.

The continuous trend in the semiconductor industry has been to buildeven increasing elaborated (and thus expensive) clean rooms with HEPA(High Efficiency Particulate Air) filters and recirculating air systemsto thoroughly control contamination by particles. Filter efficiencies of99.99999% and up to ten complete air exchanges per minute are customaryrequirements to date to obtain an acceptable level of cleanliness in theclean rooms. As a matter of fact, since different people, types ofequipment, and materials (including filters, fans, . . . ), are alsopresent in the clean room environment, the clean room cannot bemaintained as particle free as desired. In particular, although usage ofimproved clean rooms reduces particle emission by these differentsources, they do not fully contain such emissions. Moreover, admittedlyit is virtually impossible to maintain clean rooms free of particles of0.1 μm size and below.

As a matter of fact, clean rooms rated class <1 are quite impossible tobuild. In addition, chemical contaminant control in recycled air is adramatic challenge because of the complex and costly installation thusrequired. Moreover, exploitation and maintenance costs of such cleanrooms become really prohibitive. Note also, the low flexibility of themanufacturing lines constructed in such clean rooms, because existenceof walls, floors, conditioning systems, . . . etc. In addition, thetracking and management of processed wafers in such manufacturing lines,according to the host computer of the Floor Control System (FCS), aredifficult and require many manual operations.

Wafers are only partially protected against particulate contaminationand poorly protected against chemical contamination. For example,photoresists are more and more sensitive to chemical product tracescontained in the recycled air. This is an ever increasing problem, whenrecycled air is used in that respect, because HEPA filters significantlyreduce the particulate contamination level but are inoperative withrespect to contaminant chemical molecules.

In order to decrease wafer particle contamination and to enhance therebyproduction throughput, a number of techniques to design improved andclean enclosures instead of said carriers have been recently introducedfor storing and transporting the wafers to be used solely or incombination with the clean room concept.

As far as such enclosures are concerned, there are two basic schools ofthought depending upon they are of the "open type" or of the "closedtype". In the former case, the enclosure consists of a containerincluding an air cleaning device, a battery as a power source, a fanunit, and a particulate air filter. The storing chamber which isdirectly connected to the air cleaning device, has a first opening forreceiving the filtered air flow and a second opening for loading andunloading the carrier or holder containing the wafers, both openingsfacing each other. As a result, the major part of the filtered air flowsin a laminated stream passing along the surfaces of the wafers with afairly high speed, serving to protect the wafers from the intrusion ofthe particles contained in the environmental air, and removing theundesired particles originally adhered to the said wafer surfaces.

Illustrative of this first approach is U.S. Pat. No. 4,963,069 (Ref. D1)assigned to Meissner and Wurst GmbH. What is sought here is the cleaningeffect of the laminar gas flow. Note the absence of a door closing thecontainer, because the container is open on the side opposite to the fanunit.

A variant to this approach consists to have a conventional wafer carriermoving in a clean tunnel. According to this implementation, a pluralityof air blowers spaced with each other are disposed along a side wall ofa clean tunnel, thereby outer air is supplied into a tunnel zone by wayof a HEPA filter. A clean air produced within the tunnel zone iscirculated by disposing air outlets and a suction port in a zone of eachblower. Thus, a constant clean air flow can be circulated above thecarriers supporting the wafers within the clean tunnel during the wholewafer carrier transportation. An example of this approach described inU.S. Pat. No. 4,660,464 (Ref. D2) assigned to Sanki Kogyo KK. Asillustrated in FIG. 4 thereof, the physical implementation of the tunnelis relatively complex and room consuming. This approach is penalized byan obvious lack of flexibility due to the heavy implementation that isrequired.

Although conceptually simple, the "open type" container approach doesnot appear to meet the present and future manufacturing needs, and todate most technical experts seem to rely more on enclosures of the"closed type", i.e. wherein the wafers are hermetically enclosed. The"open type" approach was considered because the admitted difficulty toensure airtight sealing of the "closed type" enclosure. Should theenclosure become damaged, the wafers would be immediately contaminated.However, the same problem exists with respect to the "open type"approach, for example, should a failure occur in the air cleaning deviceor in the battery. In addition, this approach is not reliable in case ofshocks and exploitation costs are very high (the filter needs frequentchanges).

The major contribution to the "closed type" enclosure state of the artin that respect, is known under the brand name of the StandardizedMechanical InterFace (SMIF) concept. The SMIF concept was firstdescribed in the article "SMIF: a technology for wafer cassette transferin VLSI manufacturing", by Mihir Parikh and Ulrich Kaempf, Solid StateTechnology, July 1984, pp. 111-115 (Ref. D3). Further details can befound in patent specifications U.S. Pat. No. 4,532,970 (Ref. D4) andU.S. Pat. No. 4,534,389 (Ref. D5) both assigned to Hewlett-Packard Cy.In essence, according to the fundamentals of the SMIF concept, theproposal consists to reduce particle contamination by significantlylimiting particle fluxes onto wafers by mechanically ensuring thatduring transport, storage and processing of the said wafers, the gaseousmedia, generally air, surrounding the wafers is essentially stationaryrelative thereto. To have a plurality of wafers permanently surroundedby a still gaseous ambient in a clean enclosure is therefore theessential characteristics of the base SMIF concept.

Its reduction to practice results in a standard SMIF system whichbasically comprises four essential parts.

First, a small box having a still clean gaseous internal environment,referred to as the base SMIF box, consisting of a box top or coversealingly mating with a box base for hermetic tight and enclosing awafer cassette. The gaseous media surrounding the wafers results fromthe specific ambient which prevailed at the time the wafer cassette wasenclosed within the base SMIF box. A standard cassette carries about 25wafers. The base SMIF box is used for storing and carrying wafers to andfrom a processing equipment and between different processing equipments.

Second, an interface apparatus referred to as the base SMIF interfaceapparatus, which essentially consists of a removable canopy that fullycovers the input/output port of the specific processing equipment. Thecanopy demarcates a still, particle-free air volume referred to as thecanopy interior space to interface with the processing equipment. Thelatter is typically a mask aligner, an evaporator, a RIE etcher and thelike. On the other hand, the internal environment within the processingequipment is separately maintained and cleaned, so that the processingequipment need not to be necessarily installed in a clean room. The SMIFbox is placed at an interface port on top of the canopy, referred to asthe canopy port, forming an hermetic seal therewith. Then, the cassettecontaining the wafers is withdrawn from the SMIF box and transferred byan elevator/manipulator assembly to the close vicinity of the saidinput/output port for processing. Next, the wafers are extracted fromthe cassette and introduced in the processing equipment chamber, eithermanually by an operator manipulating a gripper via a glove port orautomatically using a loading/unloading robot. Thus, the base SMIF boxcan be carried in a non-clean atmosphere to an appropriate processingequipment where the wafers are processed in a controlled cleanenvironment without contamination and without having to make the entiremanufacturing facility clean.

Third, a conventional storage station provided with a number of racks orcompartments is required to store the base SMIF boxes during the waferprocessing idle times.

Fourth, a transportation system for moving the base SMIF boxes betweenthe base SMIF interface apparatus and the storage station.Conventionally, the base SMIF box is manually transported from oneprocessing equipment to another or from the storage station to oneprocessing equipment and vice versa. But, alternatively, the standardSMIF system may preferably further include an automatic transportationand handling system, typically, a robotic vehicle, usually referred toas the Automated Guided Vehicle (AGV), controlled by the FCS through awireless link.

The standard SMIF system described above may encompass a large varietyof variants, however the four basic components mentioned above stillremain: the SMIF box, the SMIF interface apparatus (enclosing theprocessing equipment), the storage station and the robotic vehicle (inthe automated version). There is a plethora of pertinent references inthat respect.

For instance, a typical base SMIF box is shown in U.S. Pat. No.4,674,939 (Ref. D6) assigned to ASYST Technologies Inc., and moreparticularly in FIG. 3. According to that reference, there is describeda sealable transportable box which defines an interior space forcontaining a number of wafers. The SMIF box includes a box top or coverand a box base which supports the box top. It further includes a boxdoor for opening and closing the box. The box door is a support which isadapted to receive the cassette holding the wafers within the saidinterior space. The wafers in the cassette are retractable with the boxdoor. Once the SMIF box has been placed down on top of the canopy portand firmly secured and sealed therewith, an elevator inside the canopy,is actuated to withdraw the canopy port door with the box door (thewafer cassette is attached thereto), down and out of the box. The wafersin the cassette can now be extracted from canopy port door/box doorassembly for subsequent adequate treatment in the processing equipmentchamber. The box top ensures hermetic sealing at the canopy portlocation thereby preventing any ingress of dirt particles within thecanopy interior space. All individual elements are carefully adjustedone with respect to the others, to provide dust-tight sealstherebetween.

The above SMIF box has a number of inconveniences. First of all, itrequires a large number of mechanical parts and the assembly thereof isquite complex. But the major inconvenience lies in that particlecontamination may still arise, in particular during transportation whena SMIF box is disturbed and during the idle time periods the wafers arenot processed when the SMIF boxes are stored under not optimal cleanroom conditions, simply because the SMIF box is not fully hermeticallysealed.

Whenever a SMIF box is disturbed, by bumping for example, many smallparticles are freed from the surface and find their way as contaminantsonto the semiconductor wafer present in the SMIF box. In particular, thegreatest the number of wafers stored in the SMIF box, the most likelythis contamination by silicon particulates. As a matter of fact, when aSMIF box becomes contaminated, it is very difficult to remove said smallcontaminant particles since the force of attraction of small particlesto the interior surfaces of the container is very high. In addition, theSMIF box shape and construction result in easy particle trapping.Scrubbing and washing techniques thus have been developed for removingsaid small particles, but they tend to be cumbersome and are notentirely effective because of the number of the different mechanicalparts and their complex assembly mentioned above.

On the other hand, the chemical contamination problem is not addressed,because the gaseous media which surrounds the wafers is the ambientwhich prevailed at the time the cassette was loaded in the SMIF box,generally a clean air ambient but with no special care with respect topotentially existing contaminant chemical molecules.

Therefore, there was still a need for an improved enclosure reallyeffective for reducing this global contamination. However, as far asparticulate contamination is concerned, two significant improvementshave been recently made to the base SMIF box, in an attempt to solvethis acute problem.

According to U.S. Pat. No. 4,739,882 (Ref. D7) again assigned to ASYSTtechnologies Inc, the first improvement consists in inserting a linerinto the SMIF box interior space surrounding the cassette (forillustration, see more particularly FIG. 3). In a preferred embodiment,the liner comprises a top liner located between the box top and the boxbase, made of a semi-rigid material which maintains a concave shape andsurrounds the cassette or holder independently of any mechanicalsupport. In another preferred embodiment, the liner further includes abase liner which is adapted to fit on the surface of the box door. Thebase liner has a sealing lip around its perimeter for exerting a forcebetween the base and the box door for encouraging a dust-tight sealtherebetween. The top liner includes a compression means for exerting aforce between the box top and box base. The top liner sits on the boxbase.

Typically, the top liner is a thin, flexible plastic liner whichrequires mechanical support to be held in a tent shape. The top liner ismade from a non-contaminating material such as a thermoplastic, examplesof which are vinyl, acrylic or fluoroplastic. Thermoplastics can beconformed by well-known techniques into relatively thin or thicktransparent films. In any embodiment, such thermoplastic films aremanufactured by processes which result in a low number of very smallcontaminant particles. A fluoroplastic is a generic name forpolytetrafluorethylene and its copolymers. One such well knownfluoroplastic is TEFLON (a trade mark of du Pont).

The liners are essentially disposable. Typically, a liner is destroyedafter one or several uses. It is expected that a liner would last 1 weekto 3 weeks under expected processing conditions. Although the linerenvironment is as clean as possible, contaminants generated by bumpingas mentioned above are present. The contaminants collected on theexternal surface of the liner, cause the liner to become dirty andbecome of potential source of contamination for the subsequentprocessing steps at the opening of the SMIF box. By replacing the liner,the container is restored to its original "clean" state without the needto replace the entire SMIF box itself. Although particulatecontamination was significantly reduced thanks to the presence of suchliners, contaminants were still noticed onto the wafer surfaces.

A further improvement is described in U.S. Pat. No. 4,724,874 (Ref. D8)again assigned to ASYST Technologies Inc. In this reference, theimproved SMIF box has a similar construction with respect to the SMIFbox just described above in U.S. Pat. No. 4,739,882. The originality nowmainly consists in the provision of a valve and a conduit in the boxdoor for communicating between the interior space of the box and a pumpwhen an injector/extractor assembly is sealably inserted in the valve.As illustrated in FIGS. 2 to 4 of U.S. Pat. No. 4,724,874, this assemblyis mounted through the port plate. The conduit includes a filter forfiltering the gas, e.g. air (or nitrogen) passing through the conduit.Still according to U.S. Pat. No. 4,724,874, the improved SMIF box onceaffixed onto the canopy port, is cleaned by alternatively pressurizingand evacuating the internal air through said filter. Thus, air may becirculated throughout the interior space of the improved SMIF boxwithout opening it.

Similarly, the base SMIF interface apparatus is also modified to take inaccount this gas cleaning improvement. It thus includes means forsupplying the gas to the improved SMIF box. Moreover, the canopyenvironment pressure is also independently controlled, because thecanopy interior space is likewise connected to the pump (num. 102 inFIG. 2). As a result, connecting the improved SMIF box interior space tothe said pump via said injector/extractor assembly, allows not only toclean the wafers but also to match the pressures between the saidimproved SMIF box interior space and the canopy interior space beforethe wafer cassette is retrieved from the improved SMIF box andintroduced in the processing equipment.

According to U.S. Pat. No. 4,724,874, the permanent still air approachthat has prevailed on the prior base SMIF boxes is no longer used,probably because it revealed to be not fully satisfactory. As a matterof fact, the prior base SMIF concept has included the principle that thewafers move from the SMIF box to the processing equipment by disturbingthe least possible amount of air within the box. The admitted advantageof this approach is that any particulate in the enclosed clean air wouldnot damage the wafers because the air remains relatively still orstagnant during the various handling/transportation steps. Now,according to U.S. Pat. No. 4,724,874 it has been found that stagnantair, too, has many particles which may also cause damage simply bystatic attraction. The first attempt to solve this problem mentionedabove with reference to U.S. Pat. No. 4,739,882, was the insertion of adisposable liner between the wafer cassette and the box top. Therecognition that the permanent still air approach causes contaminationand damage has therefore created the need explicated in U.S. Pat. No.4,724,874, for a temporary dynamic cleaning as similarly practiced insome respects in the "open type" enclosures. This air cleaning of theinternal environment of the SMIF box interior space with which thewafers are exposed is performed by successive pressurization/evacuationof the enclosed air. It aims first to release the particles, then tocollect them for subsequent elimination. The final result is therefore asignificant departure from the base SMIF still air approach whichemployed no active pressurization/evacuation of the SMIF box internalspace. It is important to notice that the air cleaning step is performedon the totality of the wafers enclosed in the cassette and only when theimproved SMIF box is affixed onto the canopy port. The essence of theimproved SMIF concept is therefore an hybrid approach to the solution ofthe contamination problem. The wafers are enclosed in a still airambient during the storage and the transportation but are subjected to avigorous dynamic air flow cleaning before being processed.

In summary, the ultimate SMIF solution described in U.S. Pat. No.4,724,874 and more particularly in FIG. 4 basically consists of animproved SMIF box for use with an improved interface apparatus.

The improved SMIF box construction still includes a housing having aninterior space for containing a wafer cassette. A plastic liner isinserted into the said interior space to surround the cassette. Theliner forming material appears to be limited to plastics because of theflexibility requirements. The box includes a box top and a box door aredesigned for tight closure. The port plate mentioned above is sealablymating to the box top. The port door includes a sealing surface and isaffixed to the port plate. The box door includes a relativelysophisticated latch mechanism for mechanically opening and closing ofthe port door. But now, the improved SMIF box further includes a conduitand a valve for establishing a communication between its interior spaceand a pump via an injector/extractor which is sealably inserted throughthe port plate when the SMIF box is affixed on the canopy port. Theconduit includes a filter for filtering the fluid passing through it.

Likewise, the improved SMIF interface apparatus still consists of acanopy which is adapted to the specific processing equipment and coversthe input/output ports thereof. In addition to the canopy port, theinterface apparatus includes a motor driven elevator/manipulatorassembly that is required to extract the wafer cassette from the SMIFbox and transport it to the processing equipment input/output port andreciprocally. As apparent from FIG. 2 of U.S. Pat. No. 4,724,874, thisis a relatively complex mechanism and a potential source of wafercontamination. But now, the improved interface apparatus furtherincludes means for connecting the interior space of the improved SMIFbox and of the canopy to a pump. It is important to notice that inaccordance with the teachings of this reference, the need for gascleaning is performed at localized areas, i.e. when the improved SMIFbox is affixed on the canopy port and thus, only for the correspondingperiods.

Still according to this ultimate SMIF solution, no significantimprovements are suggested in U.S. Pat. No. 4,724,874, as far as thestorage station and the transportation technique are concerned withregards to the base SMIF solution.

Finally, although the base SMIF solution has been ameliorated in someextent, it still remains some major inconveniences in the ultimate SMIFsolution, as it will be analyzed below.

First of all, should the SMIF boxes not fully hermetically sealed,because its interior space is not pressurized, particles from theoutside ambient are not completely prevented to enter into the immediateinternal wafer environment. Admittedly, it would be too difficult andexpensive to built totally hermetic SMIF boxes.

Recent experiments have shown that when small particles become attachedto a surface such as a SMIF box, they are not effectively removed by aircirculation and filtration techniques. As a matter of fact, circulatingand filtering air (or other inert gas) within the improved SMIF box doesnot readily remove the contamination particles which are attracted andheld in contact with the internal surfaces thereof.

During the air cleaning step which is performed only when the improvedSMIF box is affixed onto the canopy port, a relatively importantquantity of gas is injected therein and flows directly onto the wafers.Because, filtering is not 100% perfect, the particles remaining in thefiltered gas which is spread over the wafers, are likely to be depositedthereon, i.e. the reverse effect of what is sought in reality.

Consequently, the wafers are not effectively isolated from particulatecontamination during the whole sequence of fabrication steps.

In addition, the chemical contamination aspects have been completelymissed in U.S. Pat. No. 4,724,874, because the air which is employedduring said air cleaning step is the ambient air pressurized by a pump.The wafers stored in the improved SMIF box when the latter is mountedonto the canopy port are therefore in contact with an ambient whichcontains contaminant chemical molecules.

The SMIF box construction is rather complex, therefore, to clean thedifferent parts of the SMIF box is difficult. Moreover, assembling saidparts manually by an operator is also a potential source ofcontamination for the SMIF box.

SMIF boxes are not readily stackable, and typically are designed forlonely usage.

As apparent from the above, SMIF boxes are well adapted to receive acassette which carries a plurality of wafers. None of the described SMIFboxes appear to have been specifically designed for carrying a singlewafer. To date, silicon wafers are by far the most extensively used inthe semiconductor industry and with the continuous increase of thesilicon wafer diameter, SMIF boxes weight even heavier and becomeunhandy. A SMIF box of 25 silicon wafers weights about 5 kgs.Consequently, 200 mm diameter wafers seem to be the extreme limit formultiple silicon wafer SMIF boxes. By the way, the largest the capacityof the cassette, the greatest the risk of contamination by siliconparticulates during the handling/transportation steps.

On the other hand, the present trend in advanced wafer processing is toevolve towards the Single Wafer Treatment (SWT) for process uniformityand quality reasons. Single wafer processing equipments are extensivelyused for PECVD, RIE, RTP and other processes. Only some processes, suchas CVD Al because of its low deposition rate cannot be implemented thisway. Batch processing is then required. Typical advanced single waferprocessing equipments use a system configuration comprising a wafertransfer robot which transfers a wafer stored in a multiple wafercassette to and from a single wafer processing chamber generallyoperating under vacuum. In that respect, the SMIF box does not appearadequate, because when a wafer is processed in a single wafer processingequipment, the other wafers are idling and become readily contaminated.Moreover, if a SMIF box contains wafers to be processed in differentequipments, the individual wafer follow-up process is quite cumbersomeif even possible.

In addition, to date, the Single Wafer Treatment (SWT) approach appearsto be the only adequate way to fulfill the Continuous Flow Manufacturing(CFM) concept requirements in a Computer Integrated Manufacturing (CIM)environment, and in that respect again, SMIF boxes still do not appearto be well adapted. By CFM, it is meant a technique for reducing thelead times and thus the idle times. In particular, it is important tooptimize the chaining of the various processing steps in order tofabricate the chips faster. By a CIM environment, it is meant aninstallation, e.g. a manufacturing line, that is automated and fullyunder computer control.

However, the demand of simultaneously handling a plurality of wafers maycontinue. For example, because of the nature of the semiconductormaterial, e.g. gallium-arsenide (GaAs) wafers have a smaller diameterwhen compared to silicon wafers or because of the nature of theprocessing step: e.g. wafer rinsing/dipping steps are usually completedby batch. More generally, this demand may exists for other types ofworkpieces in different fields of the technology. So that, for universaluse, any valuable innovative "closed type" enclosure design should havethe ability to be simply adapted to batch processing.

As far as the improved SMIF interface apparatus is concerned, it stilldoes not appear to be adequate in some respects. First, it requires arelatively sophisticated implementation from a mechanical point of view.In particular, the step of withdrawal mentioned above, necessitatescomplex latch/release mechanisms in particular at the canopy portbetween the port door and the box door, as illustrated by FIG. 3 of U.S.Pat. No. 4,724,874, mainly because the weight of the cassette (5 Kgs).Additionally, such a complex mechanism is a potential source of wafercontamination. Moreover, the canopy delineates a large volume interiorspace. Should air be used as the internal ambient because of its lowcost, it would cause undesired oxidation effects to the exposed silicon.On the contrary, should nitrogen be used, because of the large volumedelineated by the canopy, it would result in a very costly solution.

SMIF boxes are still stored into individual racks or compartments of ahuge storage station (see FIG. 4 of the above cited article). Asmentioned above, all the handling is manual or requires a roboticvehicle. In the latter case, it is relatively a heavy and costlysolution. Generally, the robotic vehicle follows a guide line or trackthat contains an electromagnetic radiation emitting material. Theelectromagnetic radiation can be detected by a photocell sensor. Therobotic vehicle is controlled by a radio frequency communication link.The radio frequency signals are serial in nature, slow in the amount ofinformation transmitted, and may be subject to electromagneticinterferences from the other equipments used in the factory.

Finally, for a complete disclosure, note that the problem of permanentand efficient identification of the SMIF boxes has also been addressedin the SMIF solutions, for example in WO-A-87/03979 (Ref. D9) stillassigned to ASYST Technologies Inc. But, according to the SWT approach,and for many reasons, it is highly desirable now, to have the hostcomputer of the Floor Computer System (FCS) permanently tracking eachwafer individually for appropriate processing thereof instead offollowing a number of wafers contained in a cassette as practicedpursuant to the prior SMIF solutions.

As apparent from the above statements, the implementation of theproposed ultimate SMIF solution leads to many deficiencies and inherentlimitations. As a result, there is ever a primary need for an innovativesolution much more effective for totally eliminating wafercontamination, globally less complex and better adapted to the SWTapproach and to the requirements of the CFM concept in the CIMenvironment.

Applicant's inventors have thus conceived and developed a newmanufacturing concept. The essential feature of the base SMIF concept ismaintained, i.e. providing a clean enclosure with a still gaseousambient to protect the wafers (and thus eliminate the need of ultraclean rooms). Two specific features of the improved SMIF concept arealso included therein: the broad idea of having a protective liner andthat the canopy interior space can be pressurized to match the improvedSMIF box interior space pressure. The new concept is basically describedby the following key words: Contamination-free, global Automation, andSingle workpiece/wafer Treatment. The new concept will be thus referredto below by the acronym COAST.

As a matter of fact, the COAST concept significantly departs from thesaid ultimate SMIF solution on at least three points. Firstly, the mainobjective is no longer to develop improved wafer gas cleaning techniques(as described in Ref. U.S. Pat. No. 4,724,874) but instead, to eliminateany potential risk of wafer contamination including both chemical andparticulate contaminations. The objective is contamination-freeworkpiece fabrication. Secondly, it aims to reduce human intervention toa minimum. To that end, all the intervening elements are designed forbeing fully adapted to a global automation concept. Thirdly, it isessentially based upon the SWT approach, which appears to be the futureof the semiconductor wafer processing.

BRIEF SUMMARY

According to the COAST concept, a single wafer is thus stored,transported, and handled before and after processing while it ispermanently surrounded by a protective gaseous environment consisting ofan ultra pure neutral gas having a positive differential pressure withthe outside ambient, for total isolation therewith. There is noisolation breakdown at any time during the whole wafer processing stepsequence. Because, this environment is quasi still, the COAST concept istherefore broadly in compliance with the still air approach of the baseSMIF concept but it necessitates generation and preservation of thispressurized protective neutral gaseous environment.

Obviously, the COAST concept aims to comply with the Continuous FlowManufacturing concept in a Computer Integrated Manufacturingenvironment, that is of paramount importance in the present and futureof advanced semiconductor device manufacturing.

The COAST concept is articulated around three basic innovative elements.First, a family of pressurized sealable transportable containers whichstore a single silicon wafer in a pressurized protective gaseousenvironment. Second, a family of pressurized interface apparatus adaptedto said containers. The interface apparatus performs the automatic wafertransfer operation between the container and the processing equipment(associated to said interface apparatus), without breaking the saidprotective gaseous environment. Third, a family of dispatching apparatuswith a gas distribution system adapted to handle and store a pluralityof such containers during the processing idle times while permanentlymaintaining said protective gaseous environment therein. These threeinnovative base elements have been especially designed for use withconventional conveyors and for total compatibility with an informationhandling system to comply with the above mentioned CFM concept in a CIMenvironment. Consequently, these elements, when integrated with astandard computer system and conventional conveyors including intra-bayand extra-bay sections, result in a plurality of fully automated andcomputerized conveyor based manufacturing lines that have outstandingflexibility and modularity advantages. Essential features of said basicinnovative elements will be described below.

1. The containers

According to the COAST concept, the novel pressurized sealabletransportable container basically includes a box-shaped cassettereservoir provided with an access opening normally tightly closed byreleasable door means for hermetic sealing and containing therein anadequate quantity of pressurized ultra-pure neutral gas in its interiorspace. In the steady state (container door is closed), the pressurewhich prevails within the container referred to as Pcont, has a first ornominal value p to develop a small positive differential pressure Δp(typically Δp=5000 Pa) with respect to the outside ambient. The nominalpressure p must be high enough to prevent ingress of contaminants withinthe container interior space but not too high, an excess of pressurecould cause in particular undesired opening of the said door means. Thisgas is supplied by a compressed ultra pure neutral gas supplyinstallation through gas injection valve means (including a highefficiency filter). Unlike the ultimate SMIF solution which requireshuge quantity of gas to supply the canopy environment, the presentcontainer thus encloses only a limited quantity of it. The container ofthe COAST concept is made as hermetic as possible. However there isadmittedly some gas leakage during storage and transportation. Moreover,there are also some gas losses during the transfer operations mentionedabove.

In a preferred embodiment, the cassette reservoir includes a drilledinner wall that demarcates two regions within said container interiorspace: a first region in relationship with said gas injection valvemeans to form the reservoir properly said and a second region orreceptacle adapted to receive either a wafer or preferably a waferholder. The holder is provided with a transfer opening enclosing asingle wafer and is adapted to be inserted in and removed from and fromthe said receptacle through the said access opening at the beginning andat the end of the wafer processing step sequence. On the other hand, theholder includes a casing provided with minute via-holes that aredesigned, so that the gas flowing from the reservoir into the holderinterior space does not so easily penetrate therein. The holder includesmeans for softly but firmly maintaining the wafer therein. The holderwhich further plays both the roles of the liner and cassette of theultimate SMIF solution (U.S. Pat. No. 4,724,874) is preferably made of atransparent and non-contaminating material such as a plastic or pureSiO₂ (quartz). It is either disposable or cleanable. For example, if itis made of quartz, it can be cleaned for re-use. Likewise, in apreferred embodiment, the cassette reservoir is preferably made of atransparent and non-contaminating material such as a plastic or if madeof an opaque material such as stainless steel, it is provided with atransparent window so that identification data attached to the wafer canbe directly and automatically read by an appropriate reader, e.g. by abar code reader.

Said door means preferably consists of a pivoting cover provided withsealing means, typically an O-ring surrounding the access opening andclosing means, typically drawback springs, for tight and hermeticclosure. Preferably, it further includes release means adapted tocooperate with corresponding means provided to the front face of thepressurized interface apparatus for automatic opening of the saidpivoting cover.

Whenever necessary, in a departure from the SWT approach, the holder canbe readily adapted to receive a plurality of wafers instead of a singlewafer to implement a multiple wafer container version. In turn, thecontainer receptacle can also be readily adapted to receive differenttypes of multiple wafer holders, including commercially available waferholders or standard cassettes.

Moreover, the pressurized sealable transportable container overalldesign is adapted to be transported by conventional conveyors.

Finally, Applicant inventors' solution to the general problem of storingand transporting a wafer to be treated in a series of processingequipments, therefore consists in a relatively simple container whereany source of contamination is prevented, because the wafer ispermanently enclosed in a pressurized protective ultra pure neutralgaseous environment. The container is stackable and perfectly suited tothe Single Wafer Treatment approach (but easily adaptable to multiplewafer batch processing if so desired). Basically, the COAST conceptremains in line with the "closed type" enclosure approach with a stillgas environment therein. However, unlike the base SMIF solution, thestagnant gas consisting of air or an inert gas is no longer at theatmospheric pressure, but is necessarily a compressed ultra pure neutralgas that is permanently maintained under pressure with respect to theoutside ambient. As a result, any ingress of dirt particles and chemicalcontaminants into the container from the said outside ambient, isconstantly prevented. Air and some inert gases such as CO₂ react withthe silicon wafer surface and produce an undesired oxide layer, that hasto be subsequently removed.

2. The pressurized interface apparatus

Still according to the COAST concept, in a first preferred embodimentlimited to a typical single IN/OUT section version, the novelpressurized interface apparatus essentially includes a box-shapedhousing provided with two openings: a port window closed by controlledlid means located in the front face of the housing and a communicationgate opposite to said port window defining thereby a port zone orloadlock chamber therebetween. The communication gate permitscommunication between the interface apparatus interior space and theprocessing equipment chamber either directly or indirectly. Dependingupon the application or the specific treatment step performed in thechamber, the communication gate may also be provided with lid means. Theinterface interior space also contains a pressurized protective gaseousenvironment generated either directly by a connection to the said gassupply installation via specific gas injection valve means inserted inthe interface housing or indirectly, by the processing equipment itself,depending upon the application. Normally, in the steady state, theinterface interior space is at the same nominal pressure p that thecontainer interior space to ensure the positive differential pressure Δpmentioned above is obtained. A transfer robot is mounted inside theinterface interior space whose role is to grasp the wafer stored in thecontainer and to transfer it in the processing equipment for beingtreated. The pressurized interface apparatus further includes acontainer receiving zone adjacent to the housing front face having arest zone and an active zone. It still further includes actuator meansprovided with gas feeding means, so that during the waiting time thecontainer remains in the rest zone of the pressurized interfaceapparatus, the container is firmly held and permanently connected to thesaid compressed ultra pure neutral gas supply installation. Actuatormeans are intended to grip the container and move it from the rest zoneto the active zone in order to have the container sealably mating withthe port window before wafer unloading takes place.

The method of unloading the wafer from the container to transfer it intothe processing equipment reads as follows.

Assuming the container is in the waiting state, i.e. firmly maintainedby the actuator means in the rest zone in front of the port window andsupplied with gas. The interface interior space is pressurized at thesaid nominal pressure p. Once the host computer commands a transferoperation, the lid closing the port window is first opened. Theinterface interior space would be protected from contamination thanksthe gas stream which instantly would flow outwardly as a result of thepositive differential pressure existing therein. However, during thisstep of lid opening, a second pressure P is momentarily applied to theinterface interior space to ensure an adequate flow rate V (typicallyV=0.4 m/s) of the gas stream flowing outwardly. This second pressure orblower pressure aims to ensure an efficient protective gas curtain forstill better protection of the interface interior space when the lid isbeing opened. Then, the container is pulled by the actuator meanstowards to opened port window. As far as it moves closer and closer, thecontainer door is progressively released and, for the same reasons, theenclosed wafer is not contaminated. Likewise, during this step of doorrelease, the said blower pressure P is momentarily applied to thecontainer interior space. As a matter of fact, the gas stream whichflows outwardly from the container and from the port zone forms anefficient protective gas curtain which hinders any ingress of pollutantsin the two interior spaces. The actuator means moves the container untilits access opening is sealably mating against the front face of thehousing, forming thereby an hermetic sealing therewith. The O-ringsurrounding the access opening mentioned above is useful in thatrespect. This terminates the process of engaging the container. Thecontainer now lies in the active zone and is in the ready state.Because, the access opening is mating with the port window, the twointerior spaces are merged in a common interior space maintained at thenominal pressure p, unless specific requirements from the processingequipment suggests otherwise. Finally, the wafer may be then safelyunloaded from the container and loaded into the processing equipmentchamber for subsequent treatment.

Of course, the reciprocal steps must be undertaken to load the wafer inthe container after treatment. The process now includes to disengage thecontainer and move it from the active zone to the rest one where it isclamped and fed with gas. The transfer IN (unload) and transfer OUT(load) operations are thus performed without any wafer contamination. Itcan be noticed that during the short duration the container door isopened, only a very small gas stream flows over the wafer, because thepresence of said minute via-holes. In that respect, the COAST conceptmay be considered as still in accordance with the base SMIF concept of astill gaseous environment.

In this preferred embodiment, the front face of the novel pressurizedinterface apparatus is provided with means that cooperates with the doormeans for automatic opening thereof.

In another embodiment, the novel interface apparatus may be readilyadapted to the multiple wafer containers mentioned above. As aconsequence, it can be further adapted to the transfer of a waferbetween a single wafer container and a multiple wafer container and viceversa.

In a further another preferred embodiment, the novel pressurizedinterface apparatus consists of a dual section version which includestwo identical sections to the one described above, now referred to asthe IN and OUT sections. But, in this case, a container transfer deviceis required therebetween.

Finally, whichever its version, the novel pressurized interfaceapparatus is adapted to operate with conventional conveyors under fullcontrol of a computer system.

3. The dispatching apparatus with a gas distribution system

Still further according to the said COAST concept, there is proposed anovel dispatching apparatus with a gas distribution system that storesthe said pressurized sealable transportable containers in supportstations, in particular during the idle period of the wafer processing.To that end, it is adapted to permanently connect the containers to thesaid gas supply installation. Moreover, it has an handling function oftransferring the containers between the said support stations and theconveyors.

The dispatching apparatus essentially comprises two parts: atower-shaped tubular frame having tubes on which support stations orbins are affixed and a 3 dimension automatic handler including anelevator (for the Z or vertical movement) and a handling robot (forangular movement and extension in a horizontal plane) provided withgripping means adapted to the container design.

It is a major feature of the COAST concept, that each of the saidsupport stations be provided with gas injector means adapted to saidcontainer gas injection valve means and connected to the said compressedultra pure neutral gas supply installation.

The dispatching apparatus is structurally adapted to be operative withconventional conveyors, and of course, is also fully controlled by thesaid computer system.

A typical transfer operation reads as follows. For instance, once thecomputer system decides to transfer a container moving onto a conveyorto a selected support station of the dispatching apparatus for storage,the automatic handler is first activated to grasp the container with itsgripping means. Then, the container is adequately moved in the 3dimensions to be laid down in the said selected support station. It isaccurately centered and locked therein due to appropriate centering andpositioning means. Next, the gas injector means are inserted in thecontainer gas injection valve means and the gripping means are thenreleased. The container interior space is maintained at said nominalpressure p. The handler is now ready for another transfer operation.

4. The fully automated and computerized conveyor based manufacturinglines

As apparent from the above, the three disclosed innovative base elementshave been specifically designed for being adapted to operate withconventional conveyors under control of a standard computer system, tobenefit of the significant advantages that result of this type ofconvenient transportation system. Among these, one may cite reliability,simplicity, identification data (e.g. bar code) reader adaptability, lowcost, and easy total mechanical automation.

Therefore, still further according to the said COAST concept, there isprovided a plurality of fully automated and computerized manufacturinglines that comply with the CFM concept in a CIM environment. Asmentioned above, global automation is one essential feature of the COASTconcept. These manufacturing lines may be organized in a great varietyof architectures that all have the same outstanding advantages in termsof flexibility and modularity.

Typically, the novel dispatching apparatus is adapted to operate withconventional conveyors, and in particular is readily associated to thestandard by-pass station construction for transfer therebetween.Obviously, the dispatching apparatus has a key role to play in the saidnovel manufacturing lines for an efficient implementation of the CFMconcept.

In a preferred embodiment, said manufacturing line architectureincludes:

a) pressurized sealable transportable containers of the type describedabove, i.e. basically consisting of a box-shaped housing provided withan access opening sealed with releasable door means and gas injectionvalve means enclosing a wafer for subsequent treatment in a plurality ofprocessing equipments;

b) conveyor transportation means;

c) gas supply installation means comprising a compressed ultra pureneutral gas supply source and a delivery system;

d) dispatching apparatus means with a gas distribution system of thetype described above, i.e. basically comprising:

storage means for storing the containers consisting of a framesupporting a number of support stations or bins each provided with gasinjector means connected to said gas supply installation means;

handling means for transferring said containers between said bins andsaid conveyor transportation means;

e) interface apparatus means adapted to receive said containers andtransfer the wafer enclosed therein into one of said processingequipments of the type described above i.e. basically comprising:

container receiving means for receiving (sending) a container from (to)said conveyor transportation means;

a pressurized port zone or loadlock chamber with releasable lid means tointerface said container receiving means with said processing equipmentand to that end, including transfer robot means for transferring thewafer between the container and the processing equipment.

actuating/gas feeding means for moving/gas supplying the container whenplaced on the container receiving means;

f) computer means for overall control of said conveyor transportationmeans, dispatching apparatus means, gas supply installation means,interface apparatus means and said processing equipments.

OBJECTS OF THE INVENTION

It is a primary object of the present invention to provide a dispatchingapparatus with a gas supply distribution system for handling and storingpressurized sealable transportable containers.

It is another object of the present invention to provide a dispatchingapparatus including a stocker consisting of frame supporting bins forstoring the said containers wherein said bins are designed forconnecting said containers to a compressed ultra pure neutral gas supplyinstallation to maintain adequate pressurization therein.

It is another object of the present invention to provide a dispatchingapparatus whose design is adapted for integration with conventionalconveyors.

It is another object of the present invention to provide a dispatchingapparatus adapted to global automation.

It is still another object of the present invention to provide adispatching apparatus which fully complies with the Continuous FlowManufacturing concept in a Computer Integrated Manufacturingenvironment.

BRIEF DESCRIPTION OF THE DRAWINGS

FIGS. 1A-C show a schematic perspective view of the three innovativebase elements according to the COAST concept: the pressurized sealabletransportable containers, the pressurized interface apparatus and thedispatching apparatus with a gas distribution system once integratedwith a standard intelligent flexible intra-bay/extra-bay conveyor systemand a Floor Computer System (FCS).

FIGS. 2A-2C show a perspective isometric view of the base housing withno hidden lines removed detailing its construction structure, and acut-away view of the housing of FIG. 2A along line a--a, and an enlargedportion of the housing of FIG. 2A.

FIG. 3 shows a schematic perspective view of the cassette-reservoircomprised of the housing of FIG. 2A provided with a pivoting cover andgas injection valve means.

FIGS. 4A-4C show a perspective isometric view with no hidden linesremoved of a typical wafer holder enclosing a wafer, a cut-away view ofthe holder of FIG. 4A along line b--b, and an enlarged view of a portionof the holder of FIG. 4A.

FIG. 5 shows a cut-away view of the lower halves of housing of FIG. 2Band wafer holder of FIG. 4B once assembled all together.

FIG. 6 shows the assembly of FIG. 5 but using a wafer holder of adifferent design.

FIG. 7 shows a schematic exploded perspective view of the cassettereservoir and holder assembly to result in the container of the COASTconcept further including some optional components.

FIG. 8A which shows the cassette reservoir of FIG. 3 and FIG. 8B whichshows the holder of FIG. 4 when both adapted to receive a plurality ofwafers.

FIG. 9A which shows a typical commercially available wafer cassette andFIG. 9B which shows the cassette reservoir of FIG. 3 when adapted toreceive such a cassette.

FIGS. 10A and 10B show a schematic exploded perspective view of thedifferent parts composing the pressurized interface apparatus of theCOAST concept, in a typical dual section version and an enlarged portionof the apparatus of FIG. 10A.

FIG. 11 shows a schematic perspective view of the pressurized interfaceapparatus of FIG. 10 once the said different parts have been assembled.

FIGS. 12A to 120 show schematic perspective views of the pressurizedinterface apparatus during the various operating steps of the wafertransfer (loading/unloading) operations detailing thereby the sequenceof the wafer movements.

FIG. 13 shows a variant of the pressurized interface apparatus of FIG.11 once adapted to transfer a wafer from a single wafer container to amultiple wafer container.

FIGS. 14A and 14B show a schematic perspective view of a tower-shapedimplementation of the dispatching apparatus according to the COASTconcept and an enlarged view of a portion thereof.

FIG. 15 shows the preferred embodiment of the handling robot which is anessential part of the apparatus of FIG. 14A.

FIGS. 16 and 17 show two variants of the handling robot of FIG. 15.

FIG. 18 shows a wall-shaped variant of the dispatching apparatus of FIG.14A.

FIG. 19 schematically shows a first embodiment of a fully automated andcomputerized conveyor based manufacturing line architecture according tothe COAST concept.

FIG. 20 schematically shows a variant of the manufacturing linearchitecture of FIG. 19.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS INTRODUCTION

FIG. 1 shows a schematic perspective view of a partial installationdedicated to a determined process area 10, illustrating the threeinnovative base elements of the COAST concept: the container, thepressurized interface apparatus and the dispatching apparatus. Aplurality of containers 100, two interface apparatus 200, and onedispatching apparatus 300 have been illustrated in FIG. 1. A flexibleintra-bay belt conveyor system 401 ensures container transportation toand from processing equipments 500 (they can be different) within saidprocess area 10. Conventional computer system 600 comprises a generalpurpose host computer or work station 601, a Local Area Network (LAN)602 and a micro-controller 603 dedicated to this process area 10 foroverall operation control. Such a computer system 600 may be referred toas the Floor Computer System (FCS). The micro-controller 603 interfaceswith local intelligence distributed in the processing equipment, thedispatching system 300, . . . etc. In the following description, theleading role is assigned to the host computer 601, however it must beunderstood that some intelligence is delegated to the micro-controller603. A plurality of bar code readers generically referenced 604 havealso been represented in FIG. 1. Finally, a gas supply installation 700including a compressed ultra pure neutral gas supply source referenced701 and a delivery block 702 comprising manifold 703, a network of highquality stainless pipes with electropolish interior surface finish, andan adequate number of electro-valves and pressure regulators/controllersfor controlled gas flow delivery is also illustrated in FIG. 1. Outlets704 allow delivery of three pressure values: 0, p, and P, while outlets705 allow only two pressure values 0 and p. These values will beexplicated later. Usage of ultra pure neutral gas totally avoids waferchemical contamination. Note that, for sake of simplicity, the gassupply distribution network and the electrical wire network that arerequired for said overall operation control have not been represented inFIG. 1. As such, FIG. 1 may be considered showing a partial schematicview of a fully automated and computerized conveyor based manufacturingline, typically for semiconductor wafer processing. In addition, forservicing process area 10, an extra-bay conveyor 402 with its by-passstation 402A is added. Conveyors 401 and 402 are intra-bay and extra-bayelements of a conveyor transportation system 400.

Optionally, the interface apparatus 200, the intra-bay conveyor 401 andthe processing equipments 500 may be fitted in umbrella 11 for coarsedust protection. Note also, that a portable additional active umbrellamay be used atop a processing equipment when it is required to open thechamber for maintenance or set-up adjustments purposes. The activeumbrella produces the conditions adequate for a clean environment withinsaid chamber.

In one preferred embodiment of the COAST concept, the container firstincludes a box-shaped housing provided with an opening on the front facewhose access is controlled by a pivoting cover which, at rest, appliesfirmly against it for hermetic sealing. It further includes gasinjection valve means to be connected to the compressed ultra-pureneutral gas supply installation, defining thereby a pressurized interiorspace therein. As such, the housing will be referred to as the cassettereservoir. The cassette reservoir includes a drilled inner wall thatdemarcates two regions: a first region connected to said gas injectionvalve means to form the reservoir properly said and a second region orreceptacle adapted to receive a holder. The role of the drilled innerwall is to permit easy gas circulation and communication between thereservoir and the receptacle. The wafer holder is an enclosure providedwith a transfer opening on its front face defining thereby an interiorspace. The wafer is inserted in the said holder interior space throughthe said transfer opening where it is maintained by support means. Thewafer holder rear face is provided with minute via-holes so that thewafer enclosed therein is surrounded by a gaseous environment of saidneutral gas having a positive differential pressure with respect to theexternal ambient. The container interior space has a static nominalpressure p higher than the outside ambient pressure, e.g. theatmospheric pressure. Typically, the nominal pressure p is approximately5000 Pa above the pressure of the outside ambient. A perforated rimencompasses the transfer opening and creates a protective gas curtain atthe container pivoting cover opening.

Still in this preferred embodiment, the pressurized interface apparatusbasically comprises two identical input (IN) and output (OUT) sectionsfor increased throughput. The IN section first comprises a containerreceiving zone for receiving the container including a rest zone and anactive zone. In the rest zone the container is firmly secured andconnected to an outlet 704 of said gas supply installation 700 so longas it remains in the waiting state to maintain said nominal pressurementioned above. It further comprises a port zone consisting of ahousing provided with a port window closed by a port lid on the sidefacing the container and a communication gate in direct relationshipwith the chamber of a processing equipment on the opposite side. Atransfer robot mounted in the port zone interior space permits thetransfer of the wafer between the container and the input port(pre-process station) of the processing equipment. A similarconstruction applies to the OUT section. In a typical embodiment, the INand OUT sections have a common interior space. The common interior spaceis pressurized either via gas injection valve means connected to thesaid ultra pure neutral gas supply installation or by the chamberambient if adequate. A container transfer device moves the emptycontainer between the rest zones of the IN and OUT sections. The INsection is used to transfer a wafer from the container into theprocessing equipment through the port zone. The OUT section is used forthe reverse movement.

Still further in this preferred embodiment, the dispatching apparatuswith a gas distribution system first comprises means for handling andstoring the containers. To that end, it includes an automatic handlercomprising an elevator fixed on a rotating head and a handling robotprovided with gripping means to grasp the containers. It furtherincludes support means affixed to a tower-shaped frame of a verticalstocker to support the containers during storage. According to the COASTconcept, said support means are provided with gas injector means, sothat during the periods the containers are stored, a permanentconnection with the said ultra-pure neutral gas supply installation 700is secured.

Still further in this preferred embodiment, the conveyor transportsystem includes conventional flexible belt conveyors designed withstandard by-pass stations at the close proximity of said interface anddispatching apparatus.

Now turning again to FIG. 1, there is illustrated one pressurizedsealable transportable container referenced 100 being transported byintra-bay conveyor 401 and a plurality of others stored in thedispatching apparatus 300. The role of the latter is therefore to storea multiplicity of containers 100 during the processing idle times (ifany), i.e. the periods where a wafer languishes idle between twosuccessive processing steps e.g. when the appropriate processingequipment 500 is not immediately available.

According to the COAST concept, dispatching apparatus 300 has the keyrole of regulating the container continuous flow during waferprocessing. The dispatching apparatus 300 basically comprises anautomatic handler 301 and a vertical stocker 302. As a matter of fact,in full accordance with the principles of the COAST concept, thevertical stocker 302 is adapted to the container design, and inparticular it allows direct connection thereof to the said ultra-pureneutral gas supply installation 700. The gas injection valve means ofeach container 100 stored in the stocker, is permanently connected to anoutlet 705 for gas rejuvenation. The automatic handler 301 basicallycomprises a handling robot having an extending arm provided withgripping means. The handling robot is affixed on an elevator forvertical movement and is able to rotate. The vertical stocker comprisesa tower-shaped frame having tubes supporting a plurality of supportstations or bins, each being provided with gas injector means connectedto said gas supply installation 700. As a result, during the processingidle times mentioned above, an adequate pressure of said neutral gas ismaintained in the interior space of the container enclosing the wafer tobe processed. The host computer 601, according to the information storedtherein, decides which container 100 is to be transferred and whichspecific processing equipment 500 is to receive it, depending on urgencyof processing and availability of equipments. Upon host computercontrol, dispatching apparatus 300 transfers the specified container 100from stocker 302, to the input/output port of by-pass station 401A ofintra-bay flexible conveyor 401 thanks to the handling robot. Conveyors401 and 402 are conventional flexible air track or belt conveyors, suchas for example, models JETSTREAM or CARRYLINE, that are commerciallyavailable from NEU TRANS SYSTEM, Marcy en Bareuil, France. Any othertype of conveyors may be used as well. Such conveyors are well adaptedto be fully automated under computer control, and as such, are oftenreferred to as intelligent conveyors. Two different types of by-passstations have been illustrated in FIG. 1. For example, by-pass station401A comprises a single input/output port formed by an indentation inthe central portion thereof, while by-pass station 401B consists of twoseparate input and output ports. Necessary container direction changesresult from adaptation of a number of levers, piston, independentlycontrolled secondary belts, . . . that are not shown in FIG. 1, but aretrivial for the man skilled in the art. Location and processing stage ofany container, and therefore the condition of the corresponding waferenclosed therein, has to be permanently determined under the control ofthe host computer 601. This can be simply achieved thanks, for instance,to a label bearing a bar code that is stuck on a face of the container100, in combination with the bar code readers mentioned above, that areJudiciously located along the conveyors. Any other type of contactlessidentification systems would be appropriate as well. For instance, thefull automatic follow-up system referenced 0F73/EOR71, available fromBALOGH SA 75010 Paris, France.

A typical dispatching apparatus operation reads as follows. Let usassume that, within the flux of incoming containers 100 transported bythe main belt conveyor 402 in the direction of arrow 12, the hostcomputer 601 decides to transfer a specified container 100 into theby-pass station 402A. When this container reaches the input port ofby-pass station 402A, a tilt lever or a piston (not shown) pushes thiscontainer therein and the container is moved by the secondary belt ofby-pass station 402A, until it reaches the central input/output portzone thereof where a lever stops it. Next, the handling robot of handler301 grasps the container and places it in an unoccupied support stationof the vertical stocker 302. It is immediately connected to the said gassupply installation via said gas injector means.

Assuming now this container 100 stored in vertical stocker 302 has to beprocessed in a processing equipment 500 through corresponding interfaceapparatus 200. The container is first released from the said gasinjector means. Then, the handling robot sizes it and moves it in thecentral input/output port zone of by-pass station 401A of intra-bayconveyor 401 where it is laid down. Next, a lever (not shown) pushes thecontainer 100 towards the main belt of conveyor 401. The container isthen transported in the direction given by arrows 13 (as illustrated byone container 100 in FIG. 1) until it reaches the input port of by-passstation 401B in front of the corresponding interface apparatus 200. Thecontainer is then pushed into said input port still using a tilt lever(not shown), then moved towards the IN section rest zone of pressurizedinterface apparatus 200. As far as the container arrives in the INsection rest zone of interface apparatus 200, it is gripped by a pair ofcontrolled clamping actuator devices, and simultaneously connected to anoutlet 704 of said ultra-pure neutral gas supply installation 700. Thecontainer remains in the rest zone of the IN section until processingequipment 500 is available under host computer control. During thisperiod, the nominal pressure p is maintained within the containerinterior space. In normal operating conditions, the waiting time in thesaid rest zone is quite limited. Following host computer request, thecontainer is moved towards the IN section port zone.

The interface apparatus port lid is first raised and, at the end of themovement, the pivoting cover of the container (which is U-shaped) isopened and the lateral sides of the cover are slidably engaged intoslots formed in the interface apparatus housing. During this step, theblower pressure P is momentarily and successively applied to the twointerior spaces to generate an efficient gas curtain to prevent anyintrusion of contaminants therein. At the end of this step, thecontainer access opening is hermetically applied to the IN section portwindow for an hermetic seal therebetween, ensuring thereby a totalcontinuity between the two internal spaces. According to COAST concept,because internal space of the container and the one of the interfaceapparatus are both pressurized, no external contamination may affect thewafer during this whole preliminary step. When desired, the wafer isunloaded from the container by the transfer robot and transferred to theprocessing equipment 500, typically to the pre-process (or loading)station thereof, then treated in the processing equipment chamber. Atthe end of the processing, the wafer is available in the post-process(or unloading) station of the processing equipment 500, then transferredagain in the port zone of the interface apparatus for subsequent loadingin the container. During wafer processing, the empty container istransferred from the IN section to the OUT section. The same procedureas described above is employed thanks to a second pair of controlledclamping actuator devices until the container is applied against the OUTsection port window, still forming an hermetic closure therewith.Another transfer robot picks up the wafer from the processing equipmentpost-process station, and transfers it into the container. Now the saidsecond pair of controlled clamping actuator devices move back thecontainer to the rest zone of the OUT section still without breaking thegas isolation for the same reasons as mentioned above. The port lid isclosed, in turn, the container pivoting cover (due to drawback springs)is automatically closed, and further locked, hermetically sealingthereby the container interior space. The wafer enclosed therein isagain encompassed by a pressurized protective gaseous environment.Finally, upon request made by the host computer 601, container 100 ismoved back to the output port of by-pass station 401B and pushed ontoconveyor 401 for further processing or for being stocked again invertical stocker 302.

THE CONTAINERS

Single wafer containers (SWC)

Description of the preferred embodiment of the pressurized sealabletransportable container of the COAST concept will be made in the singlewafer application context in conjunction with FIGS. 2 to 7.

FIG. 2 comprises FIGS. 2A and 2B. FIG. 2A is an isometric view with nohidden lines removed of the base component of container 100 referred toas frame 101 which details its construction. FIG. 2B shows frame 101 ofFIG. 2A in a cut-away view along line aa to illustrate the lower halfthereof.

Now turning to FIG. 2, frame 101 essentially consists of a substantiallyparallelepipedic or box-shaped housing 102 with bottom, top and fourlateral faces including front and rear faces, fabricated for instance ina molded plastic material to form a solid part which can be integral ornot. Housing 102, defines an interior space 103 (not illustrated) with aslot-shaped access opening 104 on the front face and an aperture 105(wherein a highly efficient filter and a quick seal connect gasinjection valve are to be subsequently inserted) on a lateral face.Access opening size and shape are determined by the workpiece to beprocessed. Preferably, housing 102 is provided with a drilled inner wall106 which laterally defines two regions within said internal space 103.Inner wall 106 has holes 107 made therein. Number, location, and sizethereof are still defined according to the workpiece to be processedpursuant to rules detailed hereafter. Role of holes 107 is to ensureadequate gas flow circulation between reservoir 103A and receptacle103B. FIG. 2 shows a typical design with two 1 cm diameter holes closeto the middle of the inner wall lateral sides, deemed to be appropriatefor a 20 cm diameter silicon wafer application. First region 103A,adjacent to aperture 105, delineates the reservoir properly said. Secondregion 103B, accessible through access opening 104, will be thereceptacle to lodge the wafer or preferably a wafer holder. There is anumber of advantages to use the wafer holder of the COAST concept as itwill be explained later. The internal face of the housing bottom isprovided with wafer holder positioning supports referenced 108a, b andc. Likewise, the internal face of the housing top is provided withcorresponding supports referenced 108a', b' and c'. Within region 103B,inner wall 106 is provided with wafer holder positioning stoppersreferenced 109a, b and c and further includes wafer holder clampingdevices 110a and b on the two opposite lateral sides of inner wall 106at the vicinity of access opening 104. Each housing external lateralside is provided with a blind hole to allow frame 101 to be firmlygripped by a retractable finger mounted on an actuator device. As shownin FIG. 2, preferably blind hole 111A is made in a recess 112A. Similarconstruction applies to the other lateral side with blind hole 111B madein recess 112B. A metal insert may be inserted in blind holes 112A and Bto limit wear. Once retractable fingers have been engaged incorresponding blind holes 111A and 111B, frame 101 may be safely andaccurately moved. Recess profile can be designed so that the recess maybe used as a handle for easy hand manipulation or to receive a clip forassembling two (or more) frames. Housing 102 has different externalpositioning/centering means along the three X, Y and Z axes. First ofall, as illustrated in FIG. 2, the external face of housing bottom hastwo groove-shaped positioning guides 113A and B crossing its entiresurface. Reciprocally, the external face of the housing top iscorrespondingly provided with two rail-shaped positioning guides 114Aand B. Moreover, the external face of the housing bottom is providedwith two centering holes 115A and B that are useful either for movingthe frame or for its accurate positioning/centering, for instance, inthe support station of the stocker 302 whose bottom is typicallyprovided with corresponding centering pins or buttons. Moreover, whenthe said buttons are properly engaged in said holes, the container 100is perfectly and securely positioned. The external face of the housingtop is also provided with corresponding centering pins 116A and B,designed to allow easy stacking of frame 101 and an accurate positioningwith respect to the handling robot of automatic handler 301. Optionally,on its rear face, housing 102 includes an aperture 117 to receive anobservation plug for monitoring or for visual inspection as explainedbelow. Housing 102 is designed to receive door means (not shown) toclose hermetically access opening 104. In the described preferredembodiment, as illustrated later, said door means is typically apivoting cover. To that end, housing 102 has bored elements 118A and Badapted to receive the pivots of the said pivoting cover and drawbacksprings for housing hermetic closure (note that, the housing bottom hascorresponding recesses 119A and B still for stacking purposes).Optionally, housing 102 is further provided with two cover lockingdimples 120A and B to ensure total lock-up when the pivoting cover willbe applied against access opening 104 for sealing, as it will bedescribed later. Obviously, the pivoting cover must not be released evenin case the container is submitted to shocks or vibrations duringtransportation. The drawback springs mentioned above are designed tofulfill this objective. Housing 102 may be constructed in a singlemolded part to be integral or assembled by different constitutive partsusing standard bonding or fastening techniques. Simple internalconstruction with minimum asperities is recommended to facilitate itscleaning.

The detailed construction of a portion A of housing 102 at the vicinityof opening 104 is shown in the enlarged view of FIG. 2. The front faceof housing 102 includes a flange 121, whose role will be described laterin conjunction with FIG. 4. Finally, an O-ring 122 is mounted in agroove at the periphery of opening 104 to cooperate with the pivotingcover (and the front face of the interface apparatus housing asexplained later on) to make an hermetic seal therewith. Other sealingmeans such as the VATON seal sold by VAT Inc. which is directlyvulcanized onto the sealing plate, for instance, the housing front face,has outstanding qualities in terms of tightness, cleanliness andlasting. Alternatively, the O-ring may be mounted at the periphery ofthe housing front face. This terminates the description of frame 101which comprises housing 102 provided with O-ring 122.

FIG. 3 shows the cassette reservoir 123 still according to the saidfirst preferred embodiment. It includes frame 101 as described above, towhich an appropriate releasable door means is adapted. Still accordingto this preferred embodiment, said door means is an essential part ofthe cassette reservoir 123. Said door means is for closing the accessopening 104 and sealing the cavity or housing interior space from theoutside ambient for isolation therewith. Typically, pivoting cover 124is U-shaped with lateral sides 124A and B and front part 124C. Lateralside 124A is provided with a hole 125A which cooperates with boredelement 118A and pin 126A or the like. Similar construction applies tolateral side 124B in that respect to make cover 124 fully pivotable as aresult of that pivot assembly. As it will be illustrated later on, theU-shaped cover 124 will play the role of a tunnel once it is sethorizontal, i.e. when it approaches the interface port window. The pivotassembly further comprises a drawback spring (not shown) associated toeach pin 126A and B so that cover front face 124C is normally firmlyapplied against O-ring 122 for hermetic sealing. Optionally, lateralside 124B also includes a ball detenting device 127B formed in a recessthereof which cooperates with dimple 120B on the lateral side of housing102 for improved locking-up once cover 124 is firmly secured againstopening 104 due to the closing action of the drawback springs mentionedabove. Same construction applies to lateral side 124A. Each lateralside, e.g. 124B, is provided with a roller bearing, e.g. 128B, whichwill be used to automatically lift up the cover 124 when container 100is applied against the front face of the interface port housing.Cassette reservoir 123 further includes as a second essential part ofits construction, gas injection valve means 129 comprising quick connectseal plug 129A (including a non return valve) and a high efficiencyfilter 129B forming an assembly lodged in aperture 105. The quickconnect seal and the high efficiency filter are respectively availablefrom the LEE COMPANY SA Versailles, France and from MILLIPORE Corp. orPALL Corp. Because, ultra pure neutral gas is delivered from a sourcethat is quality certified by the gas manufacturer, no wafer chemicalcontamination can occur. The role of the filter 129B is to trapundesired particles, for instance, metallic particles, that could begenerated when an injector is inserted in the quick connect seal. Insummary, cassette reservoir 123 must be understood as the frame 101provided with pivoting cover 124 and gas injection valve means 129.

Details of the wafer holder construction will now be illustrated inconjunction with FIG. 4 comprised of FIGS. 4A and 4B. FIG. 4A shows theisometric view with no hidden lines removed of the wafer holder having asilicon wafer enclosed therein still pursuant to the said firstpreferred embodiment. FIG. 4B shows a cut-away view of the wafer holderof FIG. 4A along line bb to illustrate the lower half thereof. Althoughtheoretically not mandatory (e.g. it is not a requisite if the workpieceis a ceramic substrate) usage of a wafer holder is highly recommended,at least in all advanced semiconductor applications.

Now referring to FIG. 4, wafer holder 130 essentially consists of acasing 131 provided with a slot-shaped transfer opening 132 for waferinsertion/extraction. Casing general shape is designed to broadly fitthe receptacle region 103B as defined in the interior space of housing102 by inner wall 106 (FIG. 2). The rear part of casing 131 which isopposite to transfer opening 132 is provided with minute via-holes 133for gas communication between receptacle 103B and interior space 134 ofcasing 131. Via-holes 133 are so designed to cooperate with holes 107(FIG. 2) to render negligible the likelihood of wafer contamination byparticulates not filtered in the high efficiency filter 129B asexplained later in more details. The external upper and lower faces ofcasing 131 comprise each three pads 135a, b and c and 135a', b', c'.Pads 135 cooperate with their respective supports 108 of housing 102 toensure casing excellent and accurate fitting inside the cassettereservoir receptacle 103B (FIG. 2).

Casing 131 also includes stoppers 136a, b and c which cooperate withrespective stoppers 109a, b and c of housing 102 for precise centeringof holder 130 into receptacle 103B of cassette reservoir 123. Stopper109c and 136c are also designed for accurate fitting and to create asmall gap between the drilled inner wall 106 and the rear and lateralwalls of casing 131 for gas circulation therebetween depending casingcontour. As illustrated in FIG. 4A, the internal lateral face of casing131 is provided with two soft swiveling pads 137a and b. Note thatswiveling pad 137c represented in FIG. 4A is in reality affixed on theback face of cover front side 124C (see reference 137C in dotted line inFIG. 3). They all have a limited moving flexibility to facilitate waferinsertion in casing 131 and extraction thereof, as well. The swivellingpads 137 have a typical V-shaped profile to receive the silicon wafer138. As mentioned above, they are fixed to allow a certain flexibilityfor example, by a piece of an elastic material. In particular, the useof this elastic material to fix swiveling pad 137c on the internal faceof cover 124C is recommended because it improves the secureness of wafer138 when cover 124 is closed. Support pads 139a, b and c are requiredfor soft wafer support. Swiveling pads and support pads cooperate toimpede detrimental particulate generation effects due to shocks andvibrations during the handling and transportation of containers. Theswiveling pads 137 can be advantageously made from TEFLON (a trademarkof Du Pont). Support pads 139 are molded with the casing body. Theswiveling pads are designed to contact the wafer surface only at theperiphery of its edge so that the functional chips are not impacted incase of shocks. As a result, the wafer 138 is firmly secured unlike theprior base SMIF solutions. Support pads are in contact with the waferbackside surface. Note that other support pad configurations may bedesigned as well. Lateral side of casing 131 also includes two resilienttabs 140a and b that engage in clamping devices 110a and b of housing102 (FIG. 2) to accurately lock the casing 131 into receptacle 103B.Tabs 140a and b are each provided with an ear, so that the wafer holder130 is extracted from the cassette reservoir 123 at the termination ofthe wafer processing, by using a declipping gripper introduced thrutransfer opening 132. On the casing front side, a rim 141 is providedwith a plurality of perforations 142 arranged at the periphery oftransfer opening 132, whose role will be explained later. Typicaldiameter of perforations 142 is approximately in the 1-5 mm range.

Typically, the casing 131 is made from a non-contaminating plastic. Noncontaminating materials include thermoplastics, examples of which arevinyl, acrylic or fluoroplastic. Thermoplastics can be conformed bywell-known techniques into relatively thin or thick transparent films. Afluoroplastic is a generic name for polytetrafluorethylene and itscopolymers. One such well known fluoroplastic is TEFLON (a trade mark ofdu Pont).

It can be constructed by a single injected piece or by assembling thetwo upper and lower halves of casing 131 either by gluing or bonding.Due to its simple construction, casing 131 can be efficiently andreadily cleaned. However, it may be desirable to have it disposable,i.e. thrown away after each full processing cycle or even in the coursethereof if so required. Casing 131 can also be made of pure SiO₂ orquartz. In the latter case, because casing 131 is more expensive anddifficult to built, it may be desirable to have it thoroughly cleanedbefore being re-used. Other materials such as stainless steel could becontemplated as well, but would require obvious construction adaptation.

To make clear how the rim 141 mates with flange 121, the details of thecasing 131 and rim 141 are shown in the enlarged view of FIG. 4. Opening132 is in fact comprised by the juxtaposition of two sub-openings: 132Afor slidably engaging the wafer 138 in the wafer holder and 132B where avacuum operated gripper will be inserted therein to slightly lift up thewafer and hold it before it is extracted (reciprocal movement forinsertion). When holder 130 is slidably engaged in access opening 104,the rear face of perforated rim 141 is laterally moved until it appliesagainst flange 121 (see FIG. 2) for excellent peripheral mating.

As illustrated in FIG. 5, once the wafer holder 130 has been inserted inthe cassette reservoir receptacle 103B, the remaining interior space,defines a volume which fully surrounds the wafer holder, not only on itsrear and lateral faces (as apparent from FIG. 5) but also above andunder it due to the presence of supports 108 and 135. This remaininginterior space will be referred to as the internal chamber 103'B whichessentially communicates with the outside ambient thru said perforations142 (when said pivoting cover 124 is opened).

FIG. 6 shows the assembly of FIG. 5 wherein a wafer holder 130 having adifferent contour design has been illustrated. The difference only liesin the profile or contour of the holder casing which does not exhibitany longer the typical protruded rear face profile of the FIG. 4 waferholder.

FIG. 7 first illustrates the cassette reservoir 123 of FIG. 3 (withpivoting cover 124 partially removed to permit access opening 104 to bevisualized) and wafer holder 130 enclosing a wafer 138. FIG. 7 furtherillustrates some other elements that can be fitted to the cassettereservoir 123, for improved operation thereof. Container 100 is thusbasically comprised of cassette reservoir 123 and holder 130.Optionally, cassette reservoir 123 can include upper and lowerprotective shells 143 and 144. Because the preferred material for frame101 is plastic as mentioned above, due to the many handling and slidingoperations during the transport of the container on the conveyors, thecassette reservoir may wear prematurely. These shells 143 and 144 aremade of a hard and stout material, such as stainless steel, to protectthe cassette reservoir during all said handling/transportation steps.For closely fitting, upper shell 143 is correspondingly provided withrail-shaped positioning guides 145A and B and with centering buttons146A and B fitting with corresponding buttons 116A and B (note that inthis case, guides 114A and B and pins 116A and B. The flanges of shell143 have protruding members 143A and B designed for clipping in recesses112A and B. Similar construction applies to the lower shell 144, wherecorresponding grooves 147A and B may be noticed. It further includes twocentering holes (not shown) corresponding to holes 115A and B (see FIG.2). Thanks to clipping, upper and lower anti-wear shells 143 and 144firmly apply against top and bottom external faces of cassette reservoir123 for excellent protection thereof, while still allowing the stackingcapabilities mentioned above.

In addition, a label or bar code tag 148 is affixed on the rear face ofcassette reservoir 123 for identifying the container by the hostcomputer of the Floor Control System in case of there is no direct waferidentification data reading. The container is transported to variouslocations where processing operations are performed. For example, atypical remote recognition system for monitoring the progress of thecontainer enclosing the semiconductor wafer through a series ofprocessing steps is based on bar code recognition technology. Eachcontainer is provided with an optically visible bar code tag coded to beresponsive to within reading range of a bar code reader unit. A readerunit transmits a modulated light beam signal to the coded bar code tag,then reads and decodes the light beam reflected back which is collectedby an optical receiver to uniquely and permanently identify thecontainer. As illustrated in FIG. 1, reader units of this typegenerically referenced 604, are Judiciously disposed at appropriatelocations of the conveyor system 400. As a result, information generatedfrom the reader units permits monitoring the progress of eachsemiconductor wafer through the multiple processing equipments by thehost computer. Commercially available bar code tag substrates ofanodized aluminum, stainless steel, polyimide synthetic resin such asKAPTON, perfluorinated synthetic resins such as TEFLON, polyestersynthetic resin and ceramic, are adequate in all respects. However,other contactless wafer data identification systems, for instance basedon infra-red signals or the like could be envisioned as well.

A significant advantage of the disclosed single wafer container design,is the exhaustive follow-up of each wafer, and thus of the chipsresulting therefrom, not only during processing but also afterfabrication including in the field once the chips have been packaged ina system. An excellent knowledge of the wafer history allows toconstruct a data base useful for statistics maintenance or feedbackcorrective actions for reliability improvement. Note that to date, somedata are already written onto the chip backside (identifying themanufacturing periods, the references of equipments, . . . ). This trendwill surely continue if not significantly increase in the future forexample for ultra dense microprocessors.

As a matter of fact, direct wafer reading may become important in thefuture of silicon wafer manufacturing when very personalized treatmentare conducted. One can readily imagine that some typical processparameters will be writ ten directly onto the wafer to be taken inconsideration in the subsequent processing steps or even after chipfabrication, e.g. in the field for maintenance. To that end, if someconstituents of the cassette reservoir, i.e. frame 101, holder 130and/or shells 143 and 144, are made from an opaque material such asstainless steel, a transparent window may be adapted thereto for directwafer identification data reading.

If necessary, an observation plug 149, tuned on one or several specificinternal gas parameters can be inserted in optional aperture 117 offrame 101 (FIG. 2). Visual monitoring of some parameters such ashumidity, temperature, purity, . . . of the gas enclosed in reservoir103A by an operator may be required in some cases/applications. Finally,resilient clips 150A and B may be inserted in said recesses 112A and Brespectively on each housing lateral face, to interlock two containers.A number of containers can be easily piled-up for handling ortransportation.

In FIG. 7, cassette reservoir 123 is represented with pivoting cover 124in a semi-open position, out of his lodgment, and the wafer holder 130partially enclosing a wafer 138 not fully inserted in the cassettereservoir for sake of illustration. Once holder 130 fully enclosingwafer 138 is totally inserted in receptacle 103B and cover 124 closedfor hermetic sealing, container 100 may be transported or stored. It maybe transported either manually by an operator or automatically, forinstance by the intelligent flexible conveyor 400 or stored in adispatching apparatus 300, as explicated above by reference to FIG. 1.

In essence, the major characteristic of container 100 is to permanentlymaintain its interior space 103 containing the wafer holder 130(enclosing a wafer or not) under pressure and, except short periods oftransportation, to be systematically connected to the compressed ultrapure neutral gas supply installation 700 for maximum safety. Anultra-pure neutral gas, such as N2, Ar, He, . . . is introduced thereinin a conventional way by inserting a gas injector (connected to the saidgas supply installation) in the quick connect seal plug 129A (see FIG.3). As explained below, the gas injector will be a retractable nozzleadapted to said gas injection means. N2 is the preferred gas because ofits low cost. The ULPD (Ultra Low Particulate Design) gas cabinet systemsold by AIRCO is a valuable contender for gas supply installation 700.

With pivoting cover 124 closed, when the compressed neutral gas isinjected through said gas injection valve means, the gas is firstfiltered in high efficiency filter 129B before being introduced in theinterior space of container 100 to fill the reservoir 103A. Then, itpasses in receptacle 103B through holes 107 and fills the said remainingspace 103'B. Typically, hole size diameter ranges from 2 to 10 mm.Within container 100, wafer holder 130 is fully surrounded by the gas.The gas passing from reservoir 103A into chamber 103'B results in afirst baffling effect for trapping incoming particulates that couldremain. Next, it finally fills the interior space 134 of casing 131 inpassing through via-holes 133. This also produces a second bafflingeffect, very efficient because holes 107 and via-holes 133 are offsetand because of the minute size of via-holes 133. The container interiorspace is maintained at a nominal pressure p sufficient to preventingress of contaminants from the outside ambient but not too high inorder not to exert an excessive pressure on the pivoting cover 124 toavoid any undesired release thereof. Consequently, the wafer 138enclosed in holder 130 is fully encompassed by said neutral gas at anadequate positive differential pressure Δp with respect to the outsideambient. Via-hole number, size, orientation, and location may bedesigned so that the likelihood to have residual contaminantparticulates remaining in the filtered gas supplied by reservoir 103A,to reach the wafer surface, is really close to zero. Typically, via-holesize diameter ranges from 0.2 to 2 mm and are spaced from each other bya predetermined distance such as 2 to 5 mm. A very efficient additionalprotection effect to trap the said remaining particles and to divertthem from reaching the wafer is thereby produced. The combination ofholes 107 of the drilled inner wall 106 with the via-holes 133 of theperforated rear face of casing 131 to produce these two bafflingeffects, is a prominent point of the disclosed COAST concept from aparticulate trapping point of view.

The preferred range of the nominal pressure p is: 1.005-1.1 10E5 Pa toproduce a positive differential pressure Δp of about 500-10 000 Pa withrespect to the outside ambient. The typical average value isapproximately 5000 Pa. Although the container is normally designed to beas much hermetic as possible, there could be some gas leakagepossibilities especially during conveyor transportation or should longduration storage in the stocker be required. This is one of the reasonswhy the gas will have to be periodically rejuvenated. Another reason isthe necessity to open the container pivoting cover for each wafertransfer which causes non-negligible gas losses.

Now let us see how the wafer is protected from outside contaminationwhen the pivoting cover 124 is released. Normally, the container isconnected to the said gas supply installation 700 so that a protectiveneutral gas environment pressurized at the said nominal pressure p ismaintained within its interior space. Preferably, when the pivotingcover 124 has to be released, the blower pressure P is applied to saidinterior space. The aim is to produce the desired gas stream flowingoutwardly having the ade quate gas flow rate V for maximal protection.Holes 107 are so designed to allow a significant quasi laminar gas flowpassing above all the enclosed faces of the wafer holder when the cover124 is in the open position. However, these holes 107 can be onlycoarsely calibrated because their size is not really critical. Next,this gas flow passes through perforations 142 and can be directed eitherhorizontally or obliquely to create a gas curtain which protects thewafer 138 from any ingress of contaminants. Likewise, the number, size,orientation and location of perforations 142 may be so designed toachieve an efficient gas curtain for wafer protection when the pivotingcover 124 is released. It is remarkable to notice that during this timeof gas curtain generation, the wafer is quite in a still environmentbecause of the size ratio between holes 107 and via-holes 133. Because,the container 100 is connected to the said gas supply installation 700when the pivoting cover 124 is released to maintain production of saidprotective gas curtain, the container could stay in this position aslong as desired. On the other hand, should the dynamic cleaning effectmentioned above in connection with U.S. Pat. No. 4,724,874 required, itwould suffice to enlarge the diameter size of via₋₋ holes 133.

Theoretically, cassette reservoir 123 could be readily adapted to storea single wafer in a pressurized protective environment without usingwafer holder 130. In this instance, the wafer would be maintainedtherein by the supporting means generically referenced 108 in FIG. 2that have just to be adapted in that respect. However, only the firstbaffling effect mentioned above would be obtained. But the combinationof holes 107 of the drilled inner wall 106 with the via-holes 133 of therear wall of wafer holder 130 as described above to produce the secondbaffling effect mentioned above, appears nevertheless to be a requisiteas far as high value product wafers (e.g. 64 Mbit and above DRAM chips,VLSI and ULSI bipolar chips) are produced. Likewise, one may also use anon-perforated holder rim for some particular applications. The gascurtain that was produced has to be replaced by a shower effect throughthe holder opening. In this case, via-holes 133 have to be designed withlarger diameter that mentioned above.

Other container designs may be readily envisioned while still inaccordance with the basic principles of the COAST concept. Inparticular, the drilled inner wall 106 may be a drilled plate dividingthe interior space 103 in upper and lower regions. The formerconstituting the reservoir and the latter the receptacle. Underneath,this perforated plate, the air flows unhindered downwards upon the wholesurface of the wafer holder. Likewise, other solutions to the abovedescribed door means described as a pivoting cover can be implemented,e.g. magnetic doors, vertical shutters, vacuum doors . . . etc.

Finally, the container 100 is of relatively simple structural design anddo not require any complex latching mechanisms to ensure its sealing. Asillustrated in FIG. 1, handling by a belt conveyor and stacking in astocker are easy. Moreover, its unrivaled design allows usage oftransparent materials or windows for direct reading of the waferidentification data. Because of its hermetic structure and low volumereservoir, it can be inexpensively filled with costly ultra pure neutralgas. Hermetic sealing gives a real autonomy and safety to the container,should a failure occur for instance, in the gas supply installation.Usage of soft swiveling and support pads permits to significantly reducethe silicon particulate generation, that inevitably result from thefriction produced between said pads and the wafer during handling andtransportation.

Multiple wafer containers (MWC)

Indeed, the Single Wafer Treatment approach is the essence of the COASTconcept and appears of bright future, however, the demand of handling aplurality of wafers for batch processing may still continue, forinstance, for GaAs wafers (of smaller diameter sizes when compared tosilicon wafers) or for some specific processing steps such as cleaning,hot thermal processing . . . etc. Although container 100 such asdescribed in conjunction with FIGS. 2 to 7 is perfectly suited forsingle wafer storing, transport and handling, it can be readily adaptedto receive a plurality of wafers should a multiple wafer holder berequired. Thus, description of a second preferred embodiment in thatrespect, encompassing different variants adapted to multiple wafer batchprocessing, is now given with reference to FIGS. 8 and 9.

FIG. 8 is comprised of FIG. 8A and FIG. 8B wherein FIG. 8A schematicallyshows the substantive elements of cassette reservoir 123 of FIGS. 2 and3, now referenced 123', once directly derived therefrom for adaptationto receive the multiple wafer holder 130' of FIG. 8B. In turn, thelatter directly derives from the wafer holder 130 of FIG. 4.Corresponding elements bear corresponding references. Note, because ofthe relatively large volume of access opening 104', it may be worthwhileto use two gas injection valve means 129'A and B on both lateral sidesof housing box 102' instead of one. As apparent from FIG. 8, only minoradjustments substantially limited to size changes are required. However,the two holes 107 apparent in FIG. 2 now become a full set of hole pairsreferenced 107' in FIG. 8A, there is one hole pair for each wafer 138.Comments made above with respect to the number, size, and location ofholes 107 in drilled inner wall 106 (FIG. 2) still apply.

FIG. 8B shows the corresponding wafer holder 130' once adapted to storea plurality of wafers 138. For sake of simplicity, some details of thehousing 102' and of the casing 131' have not been represented in FIG.8B. Transfer opening 132' now comprises a series of slots, which, whencompared with the FIG. 4 holder, gives a typical castellated shape toits internal lateral sides. Wafer holder 130' of FIG. 8B is stillprovided with a set of via-holes 133' (not shown) corresponding to saidslots and thus in this case, in broad relationship with said set of holepairs. As a result, the efficient trapping of contaminants mentionedabove is only obtained in some extent. Finally, a piece of soft foamsuch as polyurethane foam or the like (not shown) is stuck on theinternal face of cover 124' (FIG. 8A) to maintain the wafers secured inthe holder 131' (once inserted in container 100') when cover 124' isclosed.

Some processing equipments may be designed to receive commerciallyavailable multiple wafer carriers, such as the well-known H-bar modelsdesigned and manufactured by FLUOROWARE Inc.

FIG. 9A (which corresponds to FIG. 1 of U.S. Pat. No. 4,949,848 (Ref.D10) assigned to FLUOROWARE Inc.) shows such a typical wafer carrierappropriate for being used as the cassette in the multiple wafercontainer 123' of FIG. 8A, once slightly modified.

Now turning to FIG. 9A the wafer carrier referenced 151 which has anH-shaped end wall 152 with a flange 153 supporting a horizontal indexingbar 154 commonly used for indexing the wafer carrier. Such carriers arecommercially available from FLUOROWARE Inc. under reference A192-80M andthe like.

As illustrated in FIG. 9B, the cassette-reservoir 123' (pivoting cover124" is not shown) of FIG. 8A may then be readily adapted to this typeof carrier. In this instance, the only adaptation in the cassettereservoir now referenced 123" consists in the provision of a H-barfemale attachment system 155 onto the internal face of the housingbottom of the housing now referenced 102". Obviously, the advantagesmentioned above in connection with the description of the wafer holder130 (FIG. 4), and in particular the second contaminant trapping effectand the gas curtain effect produced by perforations 142 of holder 130,are no longer obtained.

THE PRESSURIZED INTERFACE APPARATUS

The interface apparatus of the COAST concept has great versatilitypotential. In particular, it can be designed to interface either asingle wafer container (SWC) and a processing equipment (PE) or a singlewafer container and a multiple wafer container (MWC).

The SWC/PE interface apparatus

FIG. 10 shows a partially exploded view of the different elementsforming the pressurized interface apparatus 200 of the COAST concept ina dual-port version consisting of two independent IN/OUT sections tomatch most conventional processing equipments provided with respectiveinput port (pre-process or load station) and output port (post-processor unload station). Usually, a typical processing equipment furtherincludes a loadlock to interface between said ports and the treatmentchamber properly said. The said stations may or not be connected to thesaid gas supply installation 700.

In the dual-port version illustrated in FIG. 10, interface apparatus 200first includes a frame 201 which essentially consists of a box-shapedhousing 202 provided with a rim 203 at its rear face. Housing 202delineates an interior space 204 as apparent in the left most part ofFIG. 10 where the housing top surface has been removed. In FIG. 10, theinterior space 204 is common to both the IN and OUT sections, however, aseparating wall creating two independent interior spaces, one for eachsection, could be envisioned as well. The front face of housing 202 isprovided with two port windows 205A and B. Similarly, the rear face offrame 201 is provided with two corresponding communication gates 205'Aand B for communicating with the said pre-process and post-processstations respectively. The interior space between one port window andone communication gate is referred to a port zone. A pair of notches206a and b and a pair of thrusts 207a and b are disposed on the sides ofwindow 205A. Similar construction applies to port window 205B withnotches 206c and d and thrusts 207c and d. Thrusts 207a to d are eachprovided with a bored hole referenced 208a to d respectively. A lidactuator device 209A is affixed onto the top surface of housing 202. Itcomprises a fixing means 210A to attach the device to the housing topsurface, jack 211A, extension arm or piston 212A and a fork-shaped heador yoke 213A in FIG. 10, the door means consists of pivoting lid 214Awhose movement is controlled by arm 212A via yoke 213A and a boredprotruding ear fixed on the lid as illustrated in FIG. 10. The lid 214Ahas two blind holes 215a and b that cooperate with respective boredholes 208a and b and pins (not shown) to ensure its pivoting oncemovable arm 212A is retracted. As far as port window 205B is concerned,similar construction applies to lid actuator device 209B and lid 214B.The role of lids 214A and 214B is to controlably permit or preventaccess into interior space 204 through port windows 205A and 205Brespectively. Role of lids 214A and B is to maintain interior space 204fully hermetic once closed. As apparent in the left most part of FIG.10, a rotating transfer handler 216B with movable arm 217B and astandard vacuum operated fork-shaped gripper 218B is mounted and affixedon the internal face of the housing bottom within interior space 204.For instance, handler 216B body has a protrusion 219B enclosing thedriving motor which engages in recess 220B of housing 202. However, tofurther eliminate a potential contamination source, protrusion 219B maybe located outside the housing. Similar construction applies to rotatingtransfer handler 216A not visible in FIG. 10.

Interface apparatus 200 further includes two rest container receivingzones, one for each port zone (or section). In the IN section, thereceiving zone essentially consists of centering support 221A providedwith two centering rails 222a and b, which partially engages in a recess223A constructed at the right bottom of housing 202 under opening 205A.Rails 222a and b fit with corresponding grooves 224a and b. Similarconstruction applies to centering support 221B provided with rails 222cand d adapted to recess 223B and grooves 224c and d. Each containerreceiving zone is subdivided in two zones: a rest zone remote fromhousing front face and an active zone at the close vicinity of thehousing front face. Centering supports 221A and B are preferablyprovided with an aperture or perforated in the said active zone.

The IN section of interface apparatus 200 further includes a pair ofclamping actuator devices 225a and b encompassing window 205A. Actuatordevice 225a is normally fixed onto the lateral side of housing 202 onthe right of window 205A. It comprises jack 226a, movable arm or piston227a, retractable finger 228a and finally, a retractable gas feedingsystem 229a including nozzle 230a and hose 231a. The hose 231a isconnected to the compressed ultra pure neutral gas supply installation700. Actuator device 225b is of similar construction except in that theretractable gas feeding system 229a of actuator device 225a is no longerrequired. Actuator device 225b is lodged in hole 232b. Similarconstruction applies to actuator devices 225c and d in connection withopening 205B. Normally, gas feeding systems 229a and c are required toproduce the protective gas curtain at the opening of pivoting cover 124.However, occasionally in some specific applications (e.g. the workpieceis a ceramic substrate), they may be only optional. Finally, note thatother types of clamping actuator devices may be envisioned as well.

Finally, interface apparatus 200 includes a container transfer device233 to move a container from the IN section rest zone to the OUT sectionrest zone. It basically comprises an actuator device 234 sliding ingroove 235 of support 236. Actuator device 234 comprises jack 238 andmovable arm 239. A metal plate 240 (larger than shown in FIG. 10) havingtwo buttons or pins 241a and b is fixed thereon. The latter buttonsengage in corresponding holes 15A and B formed in the external bottomface of container 100 (see FIG. 2). Actuator device 234 moves the plateup and down in the vertical direction.

As explained below, the interface apparatus can be optionally providedwith an aperture 242 to be fitted with a gas injection valve assembly.Location of this aperture is not critical, for example it may beachieved in the middle of the housing front face. It is essentialaccording to the COAST concept, that the housing interior space 204which defines the two port zones be pressurized to avoid contaminationfrom the outside ambient. To that end, it has to be fully hermetic,preventing thereby any unnecessary gas leakage through port windows 205Aand B of a costly ultra-pure gas.

An enlarged view of portion referenced C of FIG. 10 is also shown toillustrate the detailed construction of notch 206b, thrust 207b andbored hole 208b mentioned above. The two lower angles of the protrudingportion of thrust 207b are rounded. Similar construction applies toother thrust 207a, c and d. This adapted profile cooperates with rollerbearings 128A and B of pivoting cover 124 (FIG. 3) for automatic openingthereof 124. Finally, FIG. 10 also illustrates the O-ring 243A and B (indotted line) which permit to lids 214A and B an hermetic sealing withthe housing front face at the periphery of port windows 205A and B.

In summary, the IN section of interface apparatus 200 thereforebasically comprises two zones: a container receiving zone whichessentially consists of centering support 221A and a port zone whichcorresponds to the portion of the housing interior space 204 locatedbetween the port window 205A and the communication gate 205'A (visiblein FIG. 11). Similar construction applies to the OUT section. Theambient and pressure which prevail within interior space 204 are usuallythose of the processing equipment pre-process and post-process stations,because communication gates 205'A and B are normally opened and lids214A and B normally hermetically seal port windows 205A and B. However,as explained later, other situations may be envisioned as well.

As apparent from FIG. 10, the OUT section is identical in all respectsto the IN section. Note that an interface apparatus comprising only asingle IN/OUT section could be also designed for processing equipmentssuch as Rapid Thermal Anneal (RTA) stations that usually process thewafers only on an individual basis and have only one input/output port.

FIG. 11 is a perspective view which shows the elements of FIG. 10 oncethe different parts have been properly assembled to construct thedual-section interface apparatus 200, assuming the top surface ofhousing 202 is transparent.

A gas injection valve means 244 (similar in all respects to device 129or not) has been inserted in aperture 242 of FIG. 8 and connected to thegas supply installation 700 via hose 245 for pressurization needs.However, alternatively, the source of pressurization may be theprocessing equipment itself thru the communication gates.

Although not clear from the latter, the container transfer device 233 ispositioned a few centimeters underneath the plane defined by the twocentering supports 221A and B. Electrical wires that control actuatordevices, the tubing network of the gas supply installation, . . . havenot been illustrated in FIG. 11 for sake of simplicity. Optionally, aremovable (transparent) cover 246 is advantageously used for dustprotection of interface apparatus 200, it may be associated with a cleanair atmosphere or not.

FIG. 11 makes apparent the different characteristics and features ofinterface apparatus 200. Besides its simplicity and rugged appearance,it has great flexibility potential for easy adaptation to anyconventional processing equipment and for extensive usage withconventional conveyors pursuant to the CFM concept in a full CIMenvironment. In addition, a defective interface apparatus can be quicklyand without effort replaced by a spare pre-qualified unit. Note also, itis possible to obtain a very high cleanliness level within the housinginterior space 204 due to the reduction of elements located within it.In accordance with the implementation illustrated in FIG. 11, the majorsource of potential contamination is the two rotating transfer handlers216A and B. However, with minimal design changes, a standard waferorienting device can also be introduced in the interface housinginterior space 204 when a specified processing equipment 500 needs tohave the wafer appropriately oriented for treatment. A bar code readeror the like can also be associated to the wafer orienting device ifrequired. Moreover, the production and exploitation cost are minima,because the volume of the housing interior space is low (reduced ultrapure gas consumption). Finally, the interface apparatus is adapted to anumber of different workpieces, for instance workpiece size changeswould only result in changes in the front face housing. Because thepressurized interface apparatus of the COAST concept operates as aloadlock, it may be designed to replace the pre-process and post processstations and the loadlock of the processing equipment mentioned above,as well.

Overall operation of the interface apparatus 200 may be now understoodby reference to FIGS. 12A to 120 which illustrate the basic sequence ofoperating steps for transferring a silicon wafer 138 from container 100to the processing equipment chamber through the IN section of interfaceapparatus 200 (transfer IN operation). The reciprocal operation, i.e.the transfer of this silicon wafer once processed from the processingequipment chamber back to the container 100 through the OUT section ofthe interface apparatus 200 (transfer OUT operation), is alsoillustrated. FIGS. 12A to 120 show the interface apparatus 200 assumingthe housing top surface is transparent to illustrate the successivemovements of rotating transfer handlers 216A and B and the differentrespective positions of the wafer 138 to be processed. The said wafer138 is enclosed in a container 100 that has to be successively unloadedand loaded. The following description implies references made to thecontainer and interface apparatus elements such as described above inconjunction with FIGS. 2 to 5 and FIGS. 8 and 9 respectively.

In the initial position illustrated in FIG. 12A, lids 214A and B arehermetically closed. The interface housing interior space 204 ispressurized with an ultra pure neutral gas. The movable arms 227a and bof clamping actuator devices 225a and b are extended, while the movablearms 227c and d of clamping actuator devices 225c and d are retracted intheir respective rest position.

Metal plate 240 of container transfer device 233 is in the low position.Input and output ports of by-pass station 401B of belt conveyor 401 arealso illustrated in FIG. 12A.

In the first sequence step, a container 100 transported on the beltconveyor 401 whose wafer is to be processed in the process equipment 500(not shown) attached to the interface apparatus 200 of FIG. 12A, ispushed in the container receiving zone of the IN section. The transferfrom the main belt conveyor 401 to the IN section can be effected bygreat variety of manner, for example, by action of a lever (not shown)coupled with a transverse rotating belt (perpendicular to the saidconveyor 401) forming said input port, and disposed in front of the INsection. Alternatively, an extension arm (not shown) activated by a jackhaving holes engaging in buttons 116A and B of container 100 (FIG. 2)could be used as well to pull the container. Similar constructionapplies to the OUT section with a reverse movement of the transversebelt in the output port thereof. Roller bearings 128A and B of container100 are efficiently used as stop members when they respectively gentlycome in contact with thrusts 207b and a. Other systems for an accuratepositioning of container 100 in the IN section rest zone, including aretractable lever, sensors, . . . may be contemplated as well.Immediately, the retractable fingers 228a and b, and the retractablenozzle 230a of clamping actuator devices 225a and b are extended andinserted in blind holes 111A and B (FIG. 2) and in the gas injectionvalve device 129 respectively, for a complete clamping and simultaneousgas feeding of container 100. The container 100 which is now permanentlyfed with gas can stay in the rest zone of the IN section as long asrequired by the host computer 601. Positioning rails 222a and b ofcentering support 221A cooperate with container grooves 113A and B (FIG.2) for an accurate container positioning. If necessary, proximitysensors can be used to detect container exact position for extremelyprecise extension of the actuator movable arms 227a and b. FIG. 12Billustrates the container 100 at this stage of the process in thewaiting position in the rest zone of the container receiving zone 221A.The two container and interface housing interior spaces are at thenominal pressure p.

The next step consists in the opening of lid 214A which closes portwindow 205A. To that end, actuator device 209A is activated, theretractable movement of arm 212A commands pivoting of lid 214A thanks tothe mechanism coupled to yoke 213A. At the end of this step, pivotinglid 214A is horizontal as illustrated in FIG. 12C. As soon as lid 214Ais opened, a continuous flow of neutral gas instantly escapes from portwindow 205A because interior space 204 of interface apparatus 200 isduly pressurized. Just before lid 214A is opened, the housing interiorspace 204 is pressurized to the blower pressure, so that Pint=P In fact,the P value is selected so that the gas stream passing through the portwindow 205A has an adequate gas flow rate typically in the 0.2-2 m/srange, preferably V=0.4 m/sec.

Once lid 214A has been fully opened, the interface interior spacepressure is reduced to the nominal pressure (Pint=p), Actuator devices225a and b pull container 100, roller bearings 128A and B are pressedagainst thrusts 207a and b which play the role of a cam because of theirspecial profile or contour mentioned above. As a result, container cover124 is progressively opened while container 100 continues to advance tocome closer and closer to port window 205A. As soon as pivoting cover124 is opened, a continuous gas flow escapes through perforations 142 ofcontainer 100 and in a small extent through transfer opening 132 toensure a complete protection of the enclosed wafer by producing theefficient gas curtain mentioned above. During this step, the said blowerpressure P is applied to the container interior space to ensure anequivalent gas flow rate V. As apparent from FIG. 3, pivoting cover 124is U-shaped. When laid horizontal, the inverted U forms a tunnel-likestructure which is an additional source of protection when the containermoves from the rest zone to the active zone. The two gas streamsgenerated internally from the container and the interface portenvironments flow outwardly downwards through the aperture orperforations formed in the centering support 221A as mentioned above.Container 100 continues its movement until its front face comes tosealably mate with the interface housing front face. O-ring 122 ofcontainer 100, then ensures an excellent hermetic sealing therebetween.FIG. 12D illustrates the container position at this stage of theprocess. Container 100 is in the ready state and stays in the activezone of the container IN section receiving zone. Pivoting cover 124 ofcontainer 100 is positioned horizontal and located underneath lid 214A.The lateral sides 124A and B of the U-shaped pivoting cover 124 areslidably engaged in slots 206a and b of interface housing front face(see FIG. 10).

The pressurized gas enclosed in the container 100 flows laminarly on allsides of the wafer holder 130, therefore fully surrounding it, beforeescaping outside through perforations 142 ensuring thereby saidefficient gas curtain at the vicinity of the container access opening.As a result, during all this critical operation, the wafer is surroundedby a protective gaseous environment having a positive differentialpressure with respect to the external ambient, which prevents anyingress of contaminants, until the container is firmly and sealablymating with the interface housing front face. At the end of this step,both interior spaces are merged in a single environment and if sodesired, connections of gas injection valve devices 129 and 244 to thegas supply installation may then be cut-off. A short idle period is nowrecommended to stabilize the said single environment. If this step iscompleted very fast, one can imagine the gas curtain produced by the aircontained in the only reservoir be adequate. If so, connection to thegas supply installation at this time may be not a requisite, however thereservoir needs to be filled again should another transfer IN/OUToperation required. Note that during all this step, the wafer is in asubstantially still environment because of the size ratio between holes107 and via-holes 133 which limits gas circulation between thereceptacle and holder interior space to produce the above mentionedtrapping effects. It is also to be noted that the step sequence of FIGS.12B to 12D is rapidly completed (approximately 2 sec) to limit gaslosses.

FIGS. 12E to 12H illustrate the different movements of the rotatinghandler 216A and the respective different positions of the wafer 138during the transfer IN operation. First, the movable arm 217A isextended through port window 205A and the vacuum operated fork-shapedgripper 218A is engaged underneath the wafer 138 within wafer holder130. The gripper gently moves into the sub-opening 132B until it arrivesat the final position, i.e. centered with respect to the wafer. Then,handler 216A slightly lift-up movable arm 217A, so that the gripper 218Agently contacts the back face of the wafer. The vacuum operated meansattached to the gripper 218A is now activated to have the wafer firmlygripped by suction (FIG. 12E). Next, the wafer 138 is pulled out fromthe container 100 and transferred through window port 205A to thehousing interior space 204, as a result of the retractable movement ofthe movable arm 217A and a first rotation of 90 degrees (FIG. 12F).Then, handler 216A rotates again of 90 degrees to allow movable arm 217Ato extend again and move the wafer through the communication gate 205' A(FIG. 12G). The wafer is laid down on the pre-process station of theprocessing equipment 500 and is now available for treatment. Movable arm217A is retracted inside the interior space 204. This terminates thetransfer IN operation for unloading container 100 and loading thepre-process station of the processing equipment. Simultaneously orsubsequently, container 100 is disengaged, i.e. it is pushed back to therest zone by the actuator devices 225a and b (FIG. 12H). During thisphase, cover 124 and lid 214A are successively closed, while thecontainer and housing interior spaces, are still not contaminatedbecause of the protective gas streams generated from the two internalenvironments that produce the gas curtain mentioned above. Althoughother variants may be envisioned, the typical scheme is to apply saidblower pressure P to generate the desired flow rate V at each time thepivoting cover 124 or a lid (214A or B) is opened. Consequently, the twointerior spaces are normally at the nominal pressure p, possibly exceptwhen the container lies in the active zone, i.e. when the said twointerior spaces are merged in a common interior space, with a singleenvironment depending the type of processing equipment. However, moresophisticated schemes can be employed that required more than the twobase pressure values p and P mentioned above. For example, two blowerpressures can be employed P1 and P2 with P1 P2, so that when thecontainer is coming to contact the interface housing front face formating, one has Pcont=P1 and Pint=P2. Values P1 and P2 are different butnot too much.

The following TABLE I summarizes the pressure values Pcont and Pint inthe two respective interior spaces during the engaging step. Thereciprocal disengaging step is totally symmetric.

                  TABLE I                                                         ______________________________________                                        OPERATION         Pcont   Pint                                                ______________________________________                                        initial waiting status                                                                          p       p                                                   preliminary to lid                                                                              p       p                                                   opening                                                                       lid opening:                                                                  start             p       p                                                   pending           p       p                                                   end               p       p                                                   preliminary to cover                                                                            p       p                                                   opening                                                                       cover opening:                                                                start             p       p                                                   pending           p       p                                                   end               p or O  p or O                                              ______________________________________                                    

The rotating handler 216A is now rotated 180 degrees to come into theinitial position shown in FIG. 12A. Then, the container 100 is releasedfrom clamping by retracting the fingers 228a and b and nozzle 230a, as aresult of the reverse of the movement described in conjunction with FIG.12B. Next, the container 100 is transferred from the IN section restzone to the OUT section rest zone of interface apparatus 200. To thatend, actuator device 234 of the container transfer device 233 is firstdriven to have metal plate 240 to pass under the container, untilbuttons 241a and b and holes 115A and B of container 100 are perfectlyaligned. The metal plate 240 is first raised by actuator device 234 toclamp the container 100, then raised again to lift-up the container byabout 5 cm to pass above actuator devices 225b and c and move itlaterally until the container is located above the OUT section restzone, as illustrated in FIG. 12I.

Next, actuator device 234 lift-down the metal plate 240, so that thecontainer 100 is laid down upon centering support 221B with a perfectalignment thanks to positioning rails 222c and d cooperating withcontainer grooves 113A and B. Finally, actuator device 234 is moved toits initial position. Once the container 100 is correctly aligned andpositioned in the OUT section rest zone, the clamping actuator devices225c and d are activated to have the sequence of movements described inconjunction with FIGS. 12B and 12C repeated. As illustrated in FIG. 12J,while container 100 remains in the rest zone of the OUT section, lid214B is released. FIG. 12K shows the respective positions of container100 now in the active zone of the OUT section container receiving zone,sealably mating with port window 205B according to a sequence of stepsdescribed above in conjunction with FIG. 12D. The processed wafer is nowavailable at the post-process station of the processing equipment forunloading. The gripper 218B is in the initial position.

Now, the rotating handler 216B transfers the wafer from the post-processstation into the container 100 by the following sequence. The handler216B is first rotated by 180 degrees about its axis, the movable arm217B extends through the communication gate 205'B, to present the vacuumoperated fork of gripper 218B beneath the wafer and grasps it byactivating the vacuum means. Then, the movable arm 217B is retracted androtated by 90 degrees as illustrated in FIG. 12L. It is rotated again by90 degrees and extended to insert the wafer into the container (FIG.12M). Finally, the said vacuum means is released and the wafer thenfreed from gripper 218B, gently moves down to stay upon the supportspads 139a, b and c and is partially inserted in swiveling pads 137a andb.

Movable arm 217B is retracted. The sequence of steps of disengaging thecontainer is the same that the one described in conjunction with FIGS.12G and H. Because now adequately fed in gas, the container 100 maysafely remain in the rest zone of the OUT section as illustrated by FIG.12N, as long as required. This terminates the transfer OUT operationwherein the wafer is transferred from the post process (unloading)station to the container.

Once the host computer decides to move again container 100, actuatordevices 225c and d push the container 100 onto the transverse conveyorbelt of the output port of by-pass station 401B. Fingers 228c and d andnozzle 230c are retracted and movable arms 227c and d are alsoretracted. Container 100 which is no longer clamped and connected to thegas supply installation (FIG. 120), is moved towards the main beltconveyor 401 and is now available for further processing or handling.Remark, the length of movable arms of actuator devices 225c and d couldbe adapted for direct container placement onto the secondary belt ofby-pass station 401B, or even onto the main belt of conveyor 401, forexample by using a telescopic arm.

The interface apparatus 200 has been described with reference to apreferred embodiment, involving a single wafer container and a standardprocessing equipment not pressurized. Preferably, pressurization of theinterface apparatus interior space being achieved by connecting gasinjection valve means 244 to the ultra pure gas supply installation.However, many variants may be envisioned.

First of all, the interface apparatus may be of a single IN/OUT portstructure or of a dual port structure with separate IN and OUT sectionsor not. The latter case is illustrated in connection with FIGS. 10 and11. According to the dual port structure of FIGS. 10 and 11, the IN andOUT sections are placed side by side, however, the IN section and theOUT section could be superimposed as well. In the latter case, thecontainer transfer device 233 would operate vertically instead oflaterally.

Moreover, the pressurized interface apparatus 200 has been describedwith externally controlled pivoting lids 214A and B, which is by far thepreferred solution. However, the man skilled in the art can easilyimagine other solutions: internal pivoting lids, or different types ofdoor systems as well. For example, the shutter door moved up and down bya shutter opening/closing mechanism as described in EP-A-462459 (Ref.D10) assigned to Dainippon Screen Mfg. Co., Ltd or a slide door asdescribed in FIG. 2 of U.S. Pat. No. 4,584,045 (Ref. D11) assigned toPLASMA-THERM Inc. However, the above described solution implemented withlid means is by far the simplest one. Note also that door means can alsobe adapted to the communication gates 205'A and B whenever necessary. Inthe latter case, the interface port zone would totally operate like aloadlock between the container and processing equipment chamber.

The SWC/MWC interface apparatus

FIG. 13 shows how the dual-port pressurized interface apparatus 200 ofFIG. 11 may be simply adapted to perform load/unload operation betweendifferent types of containers. In the example illustrated in FIG. 13, awafer stored in a single wafer container 100 is transferred in amultiple wafer container 100' (FIG. 8) or 100" (FIG. 9). Now turning toFIG. 13 and still assuming a transparent housing cover, basicallyinterface apparatus 200' consists of single port version housing 202'whose front and rear faces are adapted to the size of the container tobe fitted therewith. As a result, housing 202' has the typicalsubstantially cubic shape illustrated in FIG. 13 defining a rather largeinterior space 204'. As far as the housing front face is concerned, theconstruction is quite similar with the one illustrated in FIG. 11. Thelid 214'A which closes first port window 205 (not visible in FIG. 13) iscontrolled by actuator device 209'A. Actuator devices 225'a and b areprovided on the lateral sides of the housing 200' which also includescentering support 221'A on which a SW container 100 rests. The housingfront face further includes gas injection valve means 244' connected tothe gas supply installation 700 via hose 245' and thrusts 207a' and b'for automatic opening of container pivoting cover 124. Among the minorchanges, note a different attachment of actuator device 209'A fixed oncross bar 247 which is fastened to the thrusts 207'c and d. Rotatingtransfer handler 216' can be now driven in the Z direction thanks to anelevator piston 248. Quite similar construction is made with respect tothe rear face of housing 202' with centering support 221'B, actuatordevices 225'c and d, thrusts 207'c and d and actuator device 209'B toraise lid 214'B which closes second port window 205' facing first portwindow 205 (not visible). Although the interface apparatus 200' isadapted to make appropriate transfer of wafers between containers of thesame type or of different types, it results in a not optimized operationand involves a lot of gas losses.

A number of steps is necessary to have as many containers 100 to comeinto contact with the housing front face for wafer unloading before themultiple wafer container 100' is filled up. This sequence of stepsglobally derives from the sequence illustrated in conjunction with FIGS.12B to 12H. The SW containers may be stored in a dedicated dispatchingapparatus 300, for being subsequently loaded with their own wafer. Asclearly mentioned above, the use of multiple wafer containers is not theessence of the COAST concept. Interface apparatus 200' may be adapted tooperate with a pile of containers as mentioned above supported by a liftdevice with indexing means. Of course, the reciprocal transfer, i.e.transferring the wafers stored in a MWC into a plurality of SWC's, isalso feasible.

In still another preferred embodiment of interface apparatus 200', firstport window 205 is likewise adapted to MW containers, and the rotatingtransfer handler 216 does not move in the Z direction any longer but isadapted to grip the multiple wafer cassette (e.g. 151 of FIG. 9A) intotality for direct transfer thereof in the processing equipment throughsecond port window 205'.

THE DISPATCHING APPARATUS WITH A GAS SUPPLY DISTRIBUTION SYSTEM

According to the CFM concept, it is necessary to minimize the idletimes. Consequently, it would be desirable not to store the containersto accelerate wafer processing. However, from a practical aspect, it isrequired to regulate the manufacturing fluxes and balance the workloads.On the other hand, elements of a manufacturing line includes electroniccomponents (bar code readers, . . . ) and computer systems that are asource of potential failures. As a result, a buffer system is requiredto ensure this desired regulation. The dispatching apparatus of theCOAST concept is perfectly suited in all respects to the CFM concept.

As explained above, in conjunction with FIG. 1, the first role of thenovel dispatching apparatus of the COAST concept, is to store thecontainers 100 in the best conditions i.e. connected to the compressedultra pure neutral supply gas installation 700 during the idle timesbetween the wafer processing steps in the different processingequipments 500. The second role is to handle the containers, and inparticular to transfer the containers from the stocker to a beltconveyor or vice-versa or between two conveyors, e.g. between intra-bayand extra-bay conveyors.

Now turning to FIG. 14, in a preferred embodiment, dispatching apparatus300, which is fully automated under host computer control, is basicallymade of innovative 3 axis automatic handler 301 and vertical stocker302.

The automatic handler 301 is made of a rotatable base 303 supporting avertical elevator 304 on which a handling robot 305 comprised of anextensible horizontal arm 306 provided with gripping means 307 fixed atthe extremity thereof.

The vertical stocker 302 consists of a stainless steel frame 308 made oftubes supporting as many support stations or bins 309 as required byproduction simulations. The bins 309 are superposed in vertical columnsand those vertical columns are positioned on a circle centered about therotative axis of the handler 301. It results in the typical tower-shapedconfiguration of FIG. 14. As more particularly illustrated in theenlarged view of FIG. 14, each bin 309 consists of a support plate 310equipped with a gas feeding system 311 including a retractable nozzle312 activated by jack 313 and connected to the outlets 705 of neutralgas supply installation 700 by hoses 314. The pressure and quality ofthe enclosed gas within container 100 can be visually controlled withaccuracy thanks to observation plug 149 (FIG. 5) whenever necessary. Thegas feeding system 311 is affixed on the plate 310 thereon bycorner-plate 315. All the individual hoses 314 are connected to the gassupply installation 700.

Still in this preferred embodiment, nozzle 312 provides automaticcontrol of the gas flow within the container. When extended (container100 is present), the gas flows through nozzle 312 to feed containerinterior space, when retracted (absence of container 100) the gas flowis cutoff. As a result, only an electrical (or pneumatic) command ofnozzle movement is required.

According to another embodiment of the dispatching apparatus 300, thetubes forming the frame 308 are hollow and thus can be used for gastransportation between the gas supply installation 700 and the bins.According to this implementation, hoses 314 are directly connected tothe said tubes. In still another embodiment, the pipes are positionedwithin said hollow tubes.

Dispatching apparatus 300 facilitates transfer of containers betweenintra-bay conveyor 401 (or extra-bay conveyor 402) and the stocker 302,or between the conveyors themselves.

The detailed construction of bin 309 and robot 305 will now be given inconjunction with FIG. 15. Each bin 309 is well adapted to receive acontainer 100. To that end, plate 310 is provided with two sidewalls310A and B and two positioning buttons 315A and B that engage incorresponding holes 115A and B of container 100 (FIG. 2).

As far as robot 305 is concerned, gripping means 307 may be designed ina great variety of manners. As illustrated in FIG. 15, gripping means307 first comprises flange 316 provided with two holes 317A and B,wherein pins or buttons 116A and B formed at the external top surface ofcontainer 100 engage. A transverse bar 318 is fastened to flange 316 andcarries two gripper devices 319 A and B, that are fixed thereon. Gripperdevice 319A comprises a jack 320A, piston 321A and Jaw 322A whose end isprovided with a pad 323A which engages in recess 112A for containerclamping. Similar construction applies to gripper device 319B. Onceactivated, the two Jaws 322A and B are pivoting of about 15-30 degreesto clamp container 100.

Each bin is identified by its position (Z coordinate) in the column, theidentification number of the column and the identification number of thestocker in the factory so that each bin has his own address, which isidentified in the host computer memory. Moreover, a label is affixed infront of each bin to identify this position and thus the containerstored therein, in case of automatic handler failure. Consequently, anoperator may determine the right bin at a glance and thus the containerto be processed in a processing equipment. It is important to remarkthat, due to its unrivaled design, dispatching apparatus 300 is not onlywell adapted to work with conventional conveyors, but it may accommodatedifferent heights thereof. Standard processing equipments may haveinput/output ports at different heights, thus the use of dispatchingapparatus 300 with inclined conveyor parts, readily solves the problemof port height adaptation. Note, dispatching apparatus is also operableas a lift device.

FIGS. 16 and 17 show two variants of the gripping means 307 of FIG. 15,the improvement consists to reduce the height thereof, so that a greaternumber of containers 100 can be piled in a specified storage column ofdispatching apparatus 300. In FIG. 16, the implementation is quitesimilar to FIG. 15 still with a flange 316 provided with two actuatordevices 319'A and B. Only the structure of Jaws 322'A and B isdifferent, because U-shaped parts 324A and B, are now required.

FIG. 17 shows another variant using only one common actuator device 319'and a completely different system of jaws, whose pivoting is now madelaterally instead of vertically. Other variants, such aselectromagnetic, vacuum or pneumatic gripping means may be envisioned aswell.

Overall operation of dispatching apparatus 300 reads as follows. When aprocessing equipment, which performs a specified processing step, isgoing to be available (e.g. no more container 100 in the IN section ofthe corresponding interface apparatus 200), the host computer 601 knowswhat wafers are waiting for this step in the stocker 302 of dispatchingapparatus 300. Thus, according to scheduling defined by the FCS logisticmanagement (depending on the equipment availability, the current waferpriority, the equipment set-up parameters, . . . ), host computer 601decides which wafer and thus which container has to be moved to thisequipment. From its main memory it determines in which bin 309 ofstocker 302, the desired container 100 is stored. Now turning to FIGS.14 and 15, and assuming robot 305 is in the initial position, i.e. infront of the input/output port of by-pass station 401A with arm 306retracted. Then, under host computer control, the automatic handler 301rotates the arm 306 and moves it along elevator 304 vertically until itcomes in front of the right bin 309. Then, arm 306 is extended in orderto put the flange 316 above the wanted container 100 and in registrationtherewith. Next, the arm 306 gently goes down until flange 316 touchesthe top of the container, to have the pins 116A and B of the containerengaged in the holes 317A and B of flange 316. Then, the jacks 320A andB are actuated in order to rotate the grippers 319A and B, until thecontainer is gripped. Next, the nozzle 312 is retracted cutting-offthereby the gas connection with gas supply installation 700, the arm 306slightly moves up to release the container 100 from the pins 315A and Bof support plate 310. The arm 306 is now retracted, moved verticallydownwards and rotated to present the container 100 in front of theinput/output port of by-pass station 401A. The arm 306 is extended againand sustain the container slightly above (e.g. 1 mm or less) thesecondary conveyor belt of the by-pass station 401A. The actuatordevices 320A and B are then activated to open the jaws 322A and B, robot305 slightly goes up so that the pins 116A and 116B of container 100 arereleased from flange 316. The arm 306 is retracted and the robot 305 isready to execute the next operation. Once the container 100 is laid downonto the secondary belt of by-station 401A, it is pushed to the conveyor401 and moved to the designed process equipment 500. The man skilled inthe art may readily implement others techniques to obtain a gentlesetting of the container upon the belt conveyor. Shocks and vibrationshave obviously to be minimized. Thanks to the capability as explainedabove, of the bar code readers 604 (FIG. 1) that are Judiciouslydisposed all along the conveyors 401 to read without contact theidentification label 148 stuck on the back of the container 100 locationof the latter is continuously checked. The main memory of the hostcomputer is now informed that this bin 309 is henceforth empty andcontainer route sheet is updated. All operations described above may befacilitated should appropriate sensors be used, to detect containerposition, centering to energize the motors that control the secondarybelts, . . . under host computer control. etc.

FIG. 18 shows a dispatching apparatus referenced 300' including awall-shaped stocker variant referenced 302', of the tower-shaped stocker302 of FIG. 14, useful if more storage capacity is needed or ifnecessitated to meet manufacturing line lay-out requirements. Withrespect to FIG. 14, in FIG. 18, similar elements bear correspondingreferences. In this case, the rotatable base now referenced 303' has tobe moved along a rectilinear track 325 fixed on the floor. Note there isalso a great flexibility in designing this variant.

As apparent from FIGS. 14 and 18 the novel interface apparatus of theCOAST concept are flexible, modular fully adapted to conventionalconveyors, and thus capable of meeting all user potential needs.

FULLY AUTOMATED AND COMPUTERIZED CONVEYOR BASED MANUFACTURING LINES

For the fabrication of future advanced semiconductor chips,manufacturers are facing different factors among which the mostimportant is certainly to eliminate or at least significantly reducewafer contamination. Other key factors, such as quality (a constantthrust from the customers), higher yields, lower costs and reduced leadtimes, are closely related to wafer contamination. On the other hand,the technology continuously evolves towards increased chip integration,ever reduced minimum feature sizes, and increasing process complexity(advanced bipolar structures can require a thousand ofprocessing/treatment steps).

To achieve these desired goals the response is "to automate the fab".The global automation approach as suggested by the COAST concept is aquite satisfactory solution in all respects. It implies both mechanicalautomation and computerization. Mechanical automation means to havefully automated handling/transportation systems and processingequipments. Computerization means to have an efficient informationmanagement system, often referred to as the Floor Control Systemcombined with a complex network of wafer identification devices forpermanent wafer tracking. Merging both techniques results in a fullyautomated and computerized manufacturing line.

Of course, for a full automated operation of a manufacturing line underthe FCS control, processing equipments must be adapted in the future toprovide all necessary data/information (that are now partially suppliedto operators) in a form useable by the FCS and conversely, be responsiveto it. These data include parametric process data collected during waferprocessing, equipment availability data (down, waiting for wafer,processing complete, processing in work, . . . ), in-situ control data,and set-up data. These data further include logistic data concerningavailability of intermediate products such as: raw wafers, reticles,photoresist, . . . that are required in the semiconductor waferprocessing. Likewise, they must be capable of accepting commands fromthe FCS that traditionally have been input by an operator. Note by theway, these the reticles can be handled, stored and transported to theirappropriate locations by the same manufacturing line. An operator isthen able to load them in the lithography tools wherever required.

What is further required is a dynamically controlled movement toeliminate or at least significantly reduce the idle times, to complywith the CFM concept, and finally operate in the mode of "just-in-time"management. The FCS should know the history identity and status of allthe intervening parties: wafers, equipments, fluids, . . . in thefactory. The FCS moves the containers to equipments for further waferprocessing based on availability and wafer processing scheduling. TheFCS must be real time in nature and must operate without humanintervention to avoid misprocessing errors that are a major yielddetractor. Situations where an equipment languishes idle for extendedperiods of time in waiting for a wafer to be processed or because afterprocessing the wafer has not been removed from the equipment,contributes to a loss of efficiency in the manufacturing continuous workflow. To achieve an autonomous and real-time automated FCS, all thisinformation must be captured electronically.

Finally, for normal operation, and in case of problems (recovery plan)the operator (or the line management personnel, who has the need toknow, must be able to interrogate the different parts of the FCS, insideor outside the facility for instance, via terminals. In other words, thewafer fabrication facility must include a distributed computer network.

In conclusion, while "islands of automation" are a useful steppingstone, full achievement of the previously mentioned goals will only berealized when each piece of the manufacturing line is capable of takingits place as a full partner of such an automated factory and when theFCS is able to assimilate the flow of data it receives and in turn, toexecute the correct action.

The previous SMIF solutions as described above are far to be a totalsolution to such a desired fully automated and computerizedmanufacturing line. Still according to the COAST concept, there issuggested to merge the three above disclosed novel elements, i.e. thepressurized sealable transportable container, the pressurized interfaceapparatus and the dispatching apparatus with a conventional conveyorsystem and a standard distributed information management system referredto as the Floor Control System. The optimal integration of theseelements in that context, results in a great variety of efficient,highly flexible, modular, smart manufacturing line architecture which dorequire only minimal human intervention to operate and have outstandingrecovery capabilities to overcome any type of incidents or failures asit will be explained now.

FIG. 19 schematically illustrates a first embodiment of a novelmanufacturing line architecture that implies both conventional intra-bayand extra-bay conveyors combined with a standard distributed informationmanagement system.

Now turning to FIG. 19, there is shown a manufacturing line architecturebearing numeral 15 adapted to the COAST concept including the abovementioned base elements and organized around a loop-shaped extra-bayconveyor 402. Process area 10-1 is organized around intra-bay conveyor401-1 which transports and distributes containers 100 to the adequateprocessing equipments 501-1, 502-1, . . . (they may be identical ordifferent), via corresponding single port or dual port interfaceapparatus 201-1, 202-1, . . . etc. For example, interface apparatus201-1 and 202-1 are of the dual-port type such as described above inconjunction with FIGS. 10 to 12. Unlike, processing equipment 503-1 usestwo remote single port interface apparatus referenced 203-1 and 204-1.Finally, processing equipment 504-1 uses only a single port interfaceapparatus 205-1. The by-pass stations implemented in conveyor 401-1 arereferenced 401A-1 . . . etc. A plurality of bar code tag readers 604A-1,. . . are installed at judicious locations of intra-bay conveyor 401-1.

The process area 10-1 is associated with dispatching apparatus 300-1,which has the regulating role mentioned above and in particular to storethe containers and to transfer them to and from conveyors 402 and 401-1.Extra-bay conveyor 402 is also provided with bar code readers 604'A, . .. etc. Optionally, another dispatching apparatus can be installed on theopposite side of process area 10-1 for higher throughputs according toproduction simulations. Other process areas 10-2, . . . , 10-N can beinstalled within extra-bay conveyor 402 in manufacturing linearchitecture 15.

An input/output buffer dispatching apparatus 300 referenced 300 I/O hasalso been illustrated in FIG. 19 facing by-pass apparatus 402 I/O.Dispatching apparatus 300 I/O is loaded by containers either manually orautomatically by chaining a second extra-bay conveyor (not shown) to it.

The manufacturing line architecture 15 further includes the FloorControl System 600 now comprised of host computer 601, Local AreaNetwork 602 and a plurality of area micro controllers, one for eachprocess area, referenced 603-1, . . . etc. It further includes acompressed ultra-pure neutral gas supply installation 700-1 dedicated toprocess area 10-1. However, a central gas supply installation 700 forthe whole manufacturing line 15 may be envisioned as well. It is asignificant advantage of the COAST concept, to have manufacturing line15 operating in an average clean room and not in an ultra clean room.

FIG. 20 shows another manufacturing line architecture 16, whereinprocess areas 10-1, . . . have been only schematically illustrated.Process areas 10-1, . . . are disposed at the exterior of a centrallinear extra bay conveyor 402 which is interestingly provided withbridges 402AA', . . . for higher throughputs. In FIG. 20, thedispatching apparatus 300' I/O is typically of the wall-shaped type andincludes two vertical stockers 302'A and 302'B, and automatic handler301' which moves along rail 325 as explained above. For example,vertical stocker 302'A stores the containers whose wafers are to beprocessed (raw wafer) and stocker 302'B stores the containers once thewafers have been submitted to the full sequence of processing steps(completed wafers). Other manufacturing line architecture variants maybe envisioned as well.

Detailed operation will now be illustrated by reference to FIGS. 1 and19.

When the container 100 is pushed on the IN section rest zone ofinterface apparatus 201-1 of processing equipment 501-1, it isimmediately clamped and connected to the neutral gas supply installation700-1. Its identification is sent to the host computer 601 by reader604A-1. If necessary, host computer 601 first checks if equipment 501-1matches well the process step planned to be done on the enclosed waferto avoid any misprocessing. If yes, the procedure to open the container,unload the wafer therefrom and transfer it into the interface port zoneas described in conjunction with FIGS. 12A to 12E, is initiated. Duringthe time the wafer is being treated, the host computer 601 ispermanently informed by the equipment of the process progresses.

At the end of the processing, the wafer is loaded again in the container100 at the interface apparatus OUT section according to the proceduredescribed in conjunction with FIGS. 12J to 12N. The processing equipment501-1 informs the host computer 601 that the process step has beencompleted and the data of the route sheet of this wafer is now updated.The host computer 601 undertakes the necessary steps of what has to bedone for this container. If it is a process operation to be made byanother processing equipment, but still supplied by the same dispatchingapparatus 300-1, i.e. in the same process area 10-1, the container 100is just moved directly to it if the designated process equipment isavailable, or to the dispatching apparatus 300-1 for a temporarystorage, if not. Anyway, the container is put on the intra-bay conveyor401-1, in order to reach the next processing equipment or dispatchingapparatus 300-1.

When the next process step has to be done in another process area, e.g.10-I (not shown) the host computer 601 requests the dispatchingapparatus 300-1 to pick up the desired container 100 on the by-passstation 401A-1 of conveyor 401-1 and make all the movements necessary togrip and drop it on the by-pass station 402A where it is moved towardsmain conveyor 402. From then, it is moved to dispatching apparatus 300-Iwhere is located the right processing equipment. Note that, anadditional dispatching apparatus, such as of the type 300' describedabove, can be only used as a buffer, in manufacturing line 15, toovercome the risk of no available room in the appropriate dispatchingapparatus. When the container 100 is on the input/output port of theby-pass station of dispatching apparatus 300-I, robot 305-I is informedthat it must grip this container and put it in an available bin asdefined by the host computer 601 whose main memory is then updated. Ifthe process equipment is not immediately available, the host computer601 is aware of this container which is waiting for being processed andwhich processing equipment is appropriate in that respect. As soon asthe processing equipment is made available, this container is moved toit.

Moreover, the manufacturing lines of the COAST concept are well adaptedto a recovery plan.

In case of failure of the host computer 601, the area micro-controllerof each process area will keep in memory all the data concerning theposition and status of all the containers pertaining to it. An operatoris then able to drive manually this process area, but he will have torecord manually in the area micro-controller all the process operationshe has made on each wafer, in order to have the data of the electronicroute sheet updated in the host computer when operative again.

In case of failure of a dispatching apparatus, the operator will also beable to know through the host computer where is the right container tobe processed, to put it by hand directly on the IN section rest zone ofthe appropriate processing equipment. Thanks to the host computer 601 healso knows what is the next operation to be completed and in whichavailable bin he has to store the container enclosing the processedwafer. The operator will have to report to the host computer 601 anymovement he has made in and out the dispatching apparatus forvalidation.

More generally, all the containers are identified automatically everytime they go in and out a processing equipment or a dispatchingapparatus, in order to have the host computer to know permanently wherethey stand and what is the next process operation to be made thereon. Ifthis information is missing, there is an alarm to inform the operatorthat there is a failure and an error is reported. A corrective action isundertaken. Data that are recorded in the host computer are useful forsubsequent statistical analysis and processing equipment set-upparameter adjustment, for feed-back action.

The above solutions described by references to FIGS. 19 and 20 aretherefore an effective and low cost approach to a total solution forautomating a wafer fabrication facility in compliance with the CFMconcept, because the disclosed novel manufacturing lines and variantsthereof are capable to perform the three functions that are required inthat respect which are recited below.

1. Global automation

a) Automatic wafer tracking. Determination at any time of the physicallocation and status of containers/wafers, because each container isprovided with an identification tag and the conveyors are judiciouslyequipped with adequate readers. As a result, the containers arepermanently tracked and identified by the FCS, irrespective of beingtransported by the conveyors, stored in a dispatching apparatus, orprocessed in a processing equipment. Note that the novel containers areperfectly suited for direct wafer data identification reading.

b) Automatic container transport and dispatching. Moving the containersbetween processing equipments or within process areas is automaticallyperformed by conventional conveyors and novel dispatching apparatus,under host computer control without any human intervention.

c) Automatic processing equipment loading/unloading. All the operationsof loading/unloading the processing equipments with the wafers aresafely performed. They are fully automated under host computer controlthanks to the novel interface apparatus.

2. Contamination-free wafer fabrication

All the steps of transport, loading/unloading, storage, and dispatchingconducted within the manufacturing line are completed while the wafer isstill surrounded by a protective neutral ultra-pure gaseous environmenthaving a positive differential pressure with respect to the outsideambient. As a result, any ingress of contaminants is prevented duringthe whole sequence of treatment steps.

3. Single wafer treatment

The container and the interface apparatus are perfectly adapted to movetowards the single wafer strategy that appears to be inevitable for thefuture.

POTENTIAL APPLICATIONS OF THE COAST CONCEPT

First of all, major applications can obviously be found in thesemiconductor device manufacturing, not only in the fabrication of chipsas described above, but also in the fabrication or the handling of rawwafers, photomasks, reticles . . . that are extensively used in thisindustry.

The COAST concept can also find obvious and direct applications in otherfields of the technology, e.g. ceramic substrates, compact discs(CDs)-audio or ROM, magnetic disks, . . . etc.

More generally, it goes without saying that the novel pressurizedsealable transportable containers, the novel pressurized interfaceapparatus, the novel dispatching apparatus with a gas distributionsystem, and finally the novel fully automated and computerized conveyorbased manufacturing lines deriving therefrom can also be appliedeverywhere any contamination-free workpiece fabrication is required. Inothers words, where the fabrication of workpieces under conditionsappropriate for an ultra clean facility is necessary, without requiringthe huge clean room facility and dramatic related investments. Forexample, it is possible to extend the COAST concept for fabricatingmedicaments, foods, chemicals, . . . and to use it in the fields ofgenetic engineering, virology and the like.

We claim:
 1. A dispatching apparatus (300) with a gas supplydistribution system for handling and storing a plurality of pressurizedsealable transportable containers (100) of the type consisting of abox-shaped housing (102) provided with an access opening (104) sealed byreleasable door means (124) and gas injection valve means (129)including:an automatic handler (301) comprising:a base member with arotatable head (303); an elevator arm (304) fixed thereon; a handlingrobot (305) affixed on said elevator comprising an extension arm (306)and container gripping means (307); and, a vertical stocker (302)comprising:a frame (308) formed by a plurality of hollow vertical tubes,said frame having a plurality of support stations or bins (309) attachedthereon; wherein each bin is provided with gas injector means (311)connected on the one hand, to said gas injection valve means and on theother hand to a compressed ultra pure neutral gas supply installation(700) for maintaining a positive differential pressure Δp within thecontainer with respect to the outside ambient during the storage timewherein said hollow vertical tubes are used for gas transportation. 2.The dispatching apparatus of claim 1 wherein said plurality of hollowvertical tubes are assembled in a circle configuration centered about anaxis passing by the rotable head to produce a tower-shapedconfiguration.
 3. The dispatching apparatus of claim 1 wherein saidplurality of hollow vertical tubes are assembled in a linear directionto produce a wall-shaped configuration.
 4. The dispatching apparatus ofclaim 3 wherein the rotable head is moving along a rectilinear track(325).
 5. The dispatching apparatus of claim 1 wherein each of said binsconsists of a support plate (310) having said gas injector means (311)fixed thereon.
 6. The dispatching apparatus of claim 5 wherein said gasinjector means comprises a jack (313) actuating a retractable nozzle(312).
 7. The dispatching apparatus of claim 6 wherein said gas injectormeans operates in a first mode, when the nozzle is extended into thecontainer gas injection valve means, the connection to the gas supplyinstallation is thereby achieved, and conversely in a second mode whenthe nozzle is retracted, and the connection is thereby cut-off.
 8. Thedispatching apparatus of claim 1 wherein said gas injector means areadapted to establish a positive differential pressure Δp approximatelyin the 500-10 000 Pa range within the container.
 9. The dispatchingapparatus of claim 8 wherein said differential pressure Δp equals about5 000 Pa.